The Secret Investigator of Astor Street

Piper Sail Mystery Series #2

by Stephanie Morrill

After high school graduation, Piper Sail isn’t quite sure what her future holds—until a possible murder case lands in her lap. Filled with both the glitz and glamor of high society and the dark mafia underbelly of 1920s Chicago, The Secret Investigator of Astor Street is perfect for fans of Agatha Christie and Maureen Johnson.

Piper Sail knows what she wants: to become a detective. After all, she already solved the case of her missing best friend, and there’s no shortage of crime in 1920s Chicago. But for an eighteen-year-old society girl—even one who’s currently dating a police investigator—it simply isn’t done.

That is, until a girl asks her to dig into her brother’s recent death. The police ruled it a suicide, but she's convinced it was murder. And she wants Piper to help her prove it.

In this companion to The Lost Girl of Astor Street, Piper once again grabs her notebook and plunges into the underworld of mafia-controlled Chicago. But she’ll need all her wits and courage if she wants to become The Secret Investigator of Astor Street.

Genres: Mystery, Historical Fiction, Young Adult, Historical, Audiobook, Romance, Fiction

384 pages, Hardcover

Published August 5, 2025

About the author

Stephanie Morrill writes books about girls who are on an adventure to discover their unique place in the world. She is the author of several contemporary young adult series, as well as two historical young adult novels, The Lost Girl of Astor Street and Within These Lines. Within These Lines was a Junior Library Guild Gold Standard selection, as well as a YALSA 2020 Best Fiction for Young Adults pick. Since 2010, Stephanie has been encouraging the next generation of writers at her website, GoTeenWriters.com, which has been on the Writer’s Digest Best Websites for Writers list since 2017. She lives in the Kansas City area, where she loves plotting big and small adventures to enjoy with her husband and three children.

Reviews

[Jill Williamson]

Fantastic fun! I love Piper and adore Mariano. ♥️

I am a huge fan of Stephanie Morrill's work and loooovvveeed The Lost Girl of Astor Street, so when I found out there was going to be another Piper Sail mystery, I was so excited. Piper is out of high school now and trying to figure out what to do with her life. College doesn't appeal to her, and she doesn't want just any job. The only thing that thrills her is detective work. Problem is, it's the 1920s, and women aren't private investigators. But when a desperate girl comes along and asks Piper to look into her brother's death, Piper agrees.

I grew up on Nancy Drew novels, so this book delights me in so many ways. It's much more intriguing than any Nancy Drew novel. The historical back drop of the 1920s is delightfully fun. Lots of wit, vintage charm, and danger at every turn. Piper Sail is clever and daring and so much fun to root for. If you love mystery novels, you'll love this book. If you like jazz-age stories that take place in the 1920s, you ought to give this one a try. Highly recommended. I hope there's a book three!!!

[Marta]

10/10: 5⭐️’s

Narrator Megan Trout is excellent yet again! (I did think her Minnesotan accent was an Irish accent though😂.)

I LOVED this book. I did not want it to end!

It’s December 1924 in Chicago and 18 year old Piper Sail is on another investigation. And once again, I throughly enjoyed tagging along.

I love Piper. I love Mariano. I miss Walter. I want a dog like Sidekick.

It’s cute, sweet, funny, heartfelt, the grief is so relatable, there is mystery and mobsters and a little side dish of romance. None of it is over the top. None of it seems like too much or too little.

I HOPE Stephanie Morrill continues on with this series. I want more of Piper Sail! I am 100% a fan!!! Read/listen to book one first! Recommend both books.

Quote from the book that jumped out at me:
Chapter 22: “We have to be so careful of what we allow to define us.”

Thank you to the publisher and NetGalley for allowing me the opportunity to listen to this charming book in exchange for an honest review. All opinions are my own.

Original rating and review posted: 9/7/25
Minor edit/addition: 9/8/25
10/8/25: included publisher in thank you.

[Esme]

I sadly didn't like this book as much as the first. I think the mystery of the first had me a bit more intrigued but I still enjoyed this one. I continued liking our pre-existing characters and loved meeting new ones. This one did feel more predictable but I still enjoyed the journey.

Overall a solid series! If you're a fan of historical YA's with a young detective this could be the books for you!

Thank you Netgalley & Harper Collins for the audio copy! *all opinions are my own*

[Rachelle Cobb]

This is hands-down one of my favorite reads of 2025! An impeccable storyteller, Morrill weaves a mystery that kept me turning pages long into the night. I could not guess what happened next, but I knew I wanted to be along for the ride.

Piper Sail is the type of heroine we all long to be and to know: brave but compassionate, purposeful and intent, self-aware but willing to grow. Be still my heart to the hero, too: Mariano is top-notch.

I couldn't help but appreciate Piper’s progress through the grief over losing her best friend, her moments of doubt in her own abilities but willingness to risk it all for her new friends, and the tender family dynamics developing through it all. This cast of characters is one I immediately fell in love with in The Lost Girl of Astor Street and continued to appreciate with an added depth in The Secret Investigator. All set against the dazzling backdrop of 1920s Chicago where mobsters and the mafia and modernity intertwine.

Brava Piper Sail. Let's have a third adventure please!

[Abigail McKenna]

Okay this was SUCH a solid sequel, I am delighted. This one felt more like the typical amateur sleuth mystery, as Piper hits the beats of "what do I do with all these clues?" and "if I use a fake name no one will know who I am." and "what do you mean my fake name didn't work?" with aplomb. I love the continuation of her relationship with Mariano, who gets a special shout-out for being the first law enforcement boyfriend in a mystery that I've read who isn't vehemently against his girlfriend sleuthing, he's just against her doing it without sending him a note or something, it's refreshing. (Sure, Piper's internal drama about his ex got a bit tiresome, but she's like 18 and this is her first real boyfriend so... you do you girl)

I did actually sorta call whodunnit, but there were a lot of pieces I missed until Piper put it all together, and that was fun! Getting one sequel to "The Lost Girl of Astor Street" was lovely, but I'd 100% read several more if Ms Morrill ever decides she wants to write more. Let me know. I'm sat.

5 stars from me!

*content warnings for mentions of suicide and conversations around grief

[Angela Bell]

Piper Sail is BACK, and she’s still the cat’s pajamas!

In “The Secret Investigator of Astor Street,” Stephanie Morrill distills atmospheric prose, the nuances of grief, complex family drama, undiluted emotion, and the shadowed back-alleys of 1920’s Chicago into an intoxicating YA mystery riddled with more twists than a speakeasy escape tunnel.

Readers of “The Lost Girl of Astor Street” will thrill at being reunited with the intrepid Piper Sail as she takes a magnifying glass to a maybe murder, doggedly searching for the truth and a sense of purpose.

If you’re in need of a private eye with moxie and heart, The Secret Investigator of Astor Street is on the case!

📚 A Piper Sail Mystery
📖 1) The Lost Girl of Astor Street
📖 2) The Secret Investigator of Astor Street

I received a complimentary copy of this book from the publisher via NetGalley. A favorable review was not required. All views expressed are my own honest opinion.

[T. Rosado]

4 Stars
(Completed: 12/26/25)

I loved the previous book and was super excited that a second book was released. I liked seeing the main characters again, and the mystery was intriguing and suspenseful. I just struggled with Piper's advancement and acceptance as an investigator at her young age. Still entertaining.

[aundrea]

+4 stars for a great read

🔍📝💰

I WAS RIGHTTTTT🤌🤌
i locked in my answer early on bc usually i suspect everyone until the last minute and that feels like cheating and i was CORRECT woo!

anyways, it was so fun to be with piper again. she reminds me a lot of pip from a good girl’s guide… (idk if i said that in book 1’s review or not), and the case was pretty interesting.

the reasons why i knocked off a star:

-the pacing was a little 🤏 slow due to some repetitiveness (piper going over the same clues again and again and coming to the same conclusion)

-the romance aspect. at first i thought there was gonna be a love triangle bc jeremiah was prominent, and mariano was slacking, but then that changed… and then mariano asked to be piper’s partner and only accompanied her on one mission, for lack of better words lol. he was like there but also not?? they did have some cute moments together though, and they are a good couple, so i’ll give them that. it just seems like we never really get to see much substance to their relationship since most of their conversations are about the case she’s working on. the cannoli convo was nice though.

-i feel like the reveal was a bit of a let down. i mean it’s built up so much and then the person is just like “sigh, yes it was me 😔”. after almost getting choked, i’ll add, but still. i wanted that to be more dramatic.

-the writing style is a bit odd… scenes just cut off and transition so fast

but yeah other than that this was fun! i hope this continues to be a series.
thank you to netgalley for the arc :)

[Tracy Wood]

Piper Sail hasn't had it easy over the past year even though she lives on Astor Street in the affluent part of Chicago. Her father has remarried, she has graduated high school with no idea how she can have the future she desires and, hardest of all, she is still mourning the loss of her best friend. At least her relationship with Detective Mariano Cassano is moving along nicely. What she would really like to do is become a respected private investigator, but even in 1924 Chicago that isn't about to happen.

Attending a high school presentation ceremony at her old school wasn't something Piper was all that excited about but, amazingly, it provided her with two jobs, one for a secretarial position but the other was to undertake an actual investigation into an unexpected death! Now, all she has to do is be successful at both!

I was able to read an advanced copy of this thanks to NetGalley and the publishers, Blink, but the opinions expressed are my own. I loved this. The storyline was interesting from the start, the storytelling first class and Piper, Mariano, and the other main protagonists are great to read about. There were eight years between the first two books in this series, I hope book three will appear way before that as I already want more. Highly recommend.

[Staci]

1924 Chicago, Illinois

Sheer Delight to discover a companion novel to the author's 2017 release featuring budding investigator Piper Sail.

As a high school graduate, Piper is certain that she wants to be a private investigator, but the 1920s isn't ready for that. However...while working as a secretary at her former high school a student approaches Piper asking if she would figure out what really happened to her brother Clarence. The student is convinced that her brother didn't commit suicide. Can Piper figure out what really happened?

Lots of wonderful historical references from the time period combined with an engaging mystery equal a wonderful novel. Now please let there be another book in the series.

My gratitude to publisher Blink for a complimentary NetGalley copy of the novel. I was not required to post a review and all opinions expressed are my own.

[Madeline]

This was such a great book! As someone how really enjoys learning about this 20’s and prohibition era, I really appreciated and enjoyed how well researched it was. I fell in love with Piper’s character and quirks, how driven she is to help others and to solve a good mystery. I can’t wait to read the next book!

Thank you NetGalley and Stephanie Morrill for this ARC in exchange for my honest review.

“We have to be so careful of what we allow to define us.”
10/10 would HIGHLY recommend.

[Caroline]

Updated review 9/25/25:

A great listen. This was a reread/listen for me, and Megan Trout’s narration added so much depth of emotion I wasn’t expecting. Phenomenal.

Original review 7/1/25:

I really enjoyed this long-awaited follow up to The Lost Girl of Astor Street. I love the time period and how things are changing for women. But also how all of Piper’s relationships are changing, and how it affects her and informs her choices. I’d be really eager to read more in this series. Thanks to Blink for the ARC.

[Hanarama]

4.5 stars

A glass of wine, 1920s Jazz playlist, Candles + Piper Sail = a perfect Sunday afternoon



Set in 1920s Chicago, this historical mystery follows amateur sleuth Piper Sail as she takes on her first case as a Private Investigator. She has been hired to investigate a suspicious death that’s been too quickly ruled a suicide. As a young woman navigating high society, gang activity, and her own grief, Piper balances intuition and courage in her search for the truth.

I was lucky enough to receive both the ARC and the ALC audiobook, so I read along while listening, and it really brought the story to life! I even played a 1920s jazz playlist in the background, which made the whole experience feel completely immersive and so much fun!! Would highly recommend :)

Pros
- The 1920s setting was vivid and atmospheric, from grand mansions to smoky speakeasies

- Piper’s character has grown since the first book – she’s determined, thoughtful, and more independent

- The mystery kept a strong pace with well-placed clues. One of the things I liked most was how the investigation made sense, it wasn’t just convenient leaps of intuition, but a believable chain of clues and decisions

- HER CRIME BOARD CUPBOARD 📌 every detective needs a crime board!

- Themes of grief, self-doubt and finding purpose are handled with care

- The audiobook narration was clear and engaging – it paired really well with the text

- A perfect read to pair with jazz and a cup of tea (or whiskey 😉)



Cons

- The romantic subplot with Mariano felt underdeveloped – more distant and a sub-sub-suuubplot. Though the few scenes they did get together had some very sweet moments. MORE PIPRIANO PLEASE 😋

- A few side characters that I loved in the last book didn't return (Walter :( ) and I felt this took away from the story. Her friendships were a huge part of the last book and I missed those interactions. Though hopefully a certain crooked nosed person will make another appearance! Would be interesting to see a friendship between him and Mariano




Overall it was a smart, witty & atmospheric mystery with a strong female lead and a richly described setting. I enjoyed this even more than the first book and loved how Piper’s personal growth took centre stage. With the audiobook, eARC, and a jazz playlist going, it felt like stepping right into 1920s Chicago!! Highly recommend for fans of historical YA or cosy mysteries with a bit of an edge.


I can't wait for more Piper Sail mysteries to be written!!


Content Warnings:
References to suicide


Thank you to NetGalley and the publisher for both the eARC and the ALC audiobook in exchange for my honest review.

[Faith]

The long awaited sequel to The Lost Girl of Astor Street finds Piper Sail navigating life after high school, and taking on the case of a investigating a young man's mysterious death.
An engaging read that brings to life the class divide of the the 1920's, as Piper balances her life as a society girl where an advantageous marriage is still expected and her investigations into the seedier mafia underside of Chicago. A well written read that evokes the time period well, and does a good job of presenting complex family dynamics, and coming of age in 1920's Chicago, we see Piper's home life change as well as her relationship with Mariano mature and grow.

A solid historical fiction read that deals with tough topics, growing up, family, and love. I liked that we see Piper deal with not knowing all the answers, but pushing forward and searching for answers. She's ready for the most daring of challenges, and is spunky enough to take risks in search of truth. Great balance between the mystery, as well as character growth and interactions, with a compelling storyline. It didn't disappoint!

I received a complimentary copy of this book. Opinions expressed in this review are completely my own.

[Hailey Huntington]

If you're looking for a 1920s Chicago mystery with an amateur sleuth, look no further than Piper Sail! The mystery will keep you wondering, while Morrill skillfully leaves the clues you need all along the way.

I appreciated how Morril tactfullly and purposefully wove in Piper's hurt, trauma, and healing from Lydia's death throughout the book and even tied it into the plot. It added an extra level of believability.

While it made sense for Mariano to feature less in the story with the coming-of-age and independence character arc for Piper, I did wish that he'd been involved more beyond the romance subplot.

Fans of The Lost Girl of Astor Street will enjoy getting to tag along with Piper for another case.

Cautions: moderate romance; several kisses; one blasphemy; the case Piper investigates is initially believed to have been suicide, and the topic comes up several times; brief, non-graphic moderate violence

[Phoenix2]

Big Thanks to Netgalley and the Publisher for the advanced copy! I received a complimentary copy of this book. Opinions expressed in this review are completely my own

'The Secret Investigator of Astor Street' is the second book in the 'A Piper Sail Mystery' series.

The second book is as good as the first one, with Piper venturing into yet again another mystery, which was as twisty and intriguing as the one in the first book.

The atmosphere was great as well, and there were a lot of details that contributed to it a lot.

The character development was also intense and well-crafted.

Finally, the audiobook was well narrated and produced, but the time skips were not well handled.

[Katherine]

I loved The Secret Investigator of Astor Street. Morrill blends history, humor, and danger beautifully, the twists and turns are so fun, and the characters are well developed and surprising in a real-life way that has stuck with me days after turning the last page. Be forewarned that this book is really hard to put down!

[Elena]

Not quite as exciting as reading the first book as a mystery loving teenager, but fun all the same! A well paced mystery with a spunky detective and a great cast of characters. And a Chicago setting!!

[Maria]

This was just as wonderful as the first one! I loved getting to know Piper better and seeing her in action on her first case where she doesn’t have a connection to the victim. This requires her to use her smarts and personality to get the information she needs. The blossoming relationship with Mariano as well as the complicated relationships she has with her family add a layer of depth to the story that had me just as captivated as the mystery. I can’t wait for the next one!

I received a copy from #NetGalley and #HarperCollinsFocus for an honest review.

[jenna williams]

thank you. more, please.

[allison riera :)]

gosh I had forgotten how much I love Piper & Mariano.

[Charlotte Tamm]

Rounded up from 3.5

[Rachel]

To quote Thor: “This drink. I like it. Another!”

[Faith]

Love love love! I expected to like this book less than book 1 (which blew me away tbh) but found myself enjoying it just as much, but in a slightly different way. So happy to have found these!

[Sacha]

Piper Sail is my new favorite private investigator. I am going the be very disappointed if there isn't a book # 3. Finger's cross that a sequel is on it's way soon.

[Lee]

The year is 2019. A friend and I buddy-read Lost Girl of Astor Street the previous year, and now, Stephanie Morrill is teaching at a student writing conference we're attending. After one of her talks, we go up to talk to her. And asked her about why Lost Girl seemed to imply (spoilers for that book) Lydia was still alive. She chuckled and said that scene probably didn't come across the way she'd meant it to. Alas.

Fast forward to this book. The victim is definitely, completely, 100% dead before the book starts. I'm not going to say my friend and I can take credit for that, but I'm also not saying that isn't at all a possibility. 🤣

In all seriousness, this book is fun. Couple things bugged me, other things I liked better. The usual. But it is a fun time overall.

[TT]

I really enjoyed the first one, and this surpassed that. The mystery was more intriguing, and had more twists and turns than the first one. The characters relationships continued developing well, and I really enjoyed the author acknowledging how people would have actually treated Piper in the 1920s, rather than just pretending that her working as a private detective would have been fine. I also thought Piper’s own thoughts on being a private detective played out really nicely, from ‘oh no I can’t’ to ‘I work for a private detective’ to ‘I am a private detective’. Overall really enjoyable. Thanks to Netgalley for the ARC.

[Acantha]

Move over Nancy Drew, a new young female detective is in town.

I really enjoyed this story. The mystery was a much stronger one than the first book and its clear that the author has gotten more confident with her characters and her setting. Piper is introduced to a girl whose brother committed suicide - a fact the sister refuses to accept. Eager to prove herself and find her own way in the world, she takes on the case but it quickly proves to be one full of many twists and turns. The case was fun, Piper deserved to solve it.

Just as good as Piper's investigation was the way in which the author explored the aftermath of a tragedy. Grief litters the pages, different people dealing with different issues in different ways. Each person's grief feels very real and honest, sometimes raw.

Mariano, Piper's boyfriend, is as adorable as ever, albeit with his own issues. My only compliant was there wasn't nearly enough of him, but I love how comforting and supportive he was, as well as proud of who she was.

~Thank you to NetGalley for the ARC in return for an honest review~

[✞emerson✞ [levi coldwell’s version]]

3 stars ⭐️

Ayyyy I was so happy when I saw this got published
Overall I was just so glad to be back in the world of Piper Sail
The book wasn't as good or hooking as 'Lost Girl' in my opinion and I REALLY, REALLY wish there was more Piper and Mariano (I thought we were gonna get more closure on their relationship in the end, but it mostly felt like Mariano was working the whole book and then it just ended?!?!?!) But they're still cute as ever in the interactions we did get from them 😍

I was pretty sure I knew who the murderer was like, halfway through the book (and I ended up being right which made it a bit less fun lol)
The mystery just felt a less developed and suspenseful than in book one I guess

But I still enjoyed it very much!!

[Grandma Susan]

The author catches the essence of the time period and setting well. Lots of atmosphere in this book. Piper isn’t your typical Society girl and I love her for it. Quite unconventional. The story moved along well and had me engaged. The mystery was intriguing. Outstanding narration. Highly recommend both books in the series.

I was blessed with an audio ARC. Thank you NetGalley. The opinions expressed are my own and unbiased. Enjoy!