Don’t Cross Mo Ellery

by Birdie Horne

A laugh-out-loud mystery following the indomitable hot mess Mo Ellery, whose job as a school crossing guard pulls her into an unhinged murder investigation.

Mo Ellery’s 29th birthday is a disaster. After one small accident—the exposure of her boyfriend’s genitals (well, maybe not that small) on a work video call—she manages to get fired, dumped, and kicked out of their overpriced Chicago apartment. Luckily, a sign appears to guide Mo to her new “Looking for flexible part-time work? Become a school crossing guard!” It’s everything Mo has been looking health insurance. How hard can it be?

A few weeks later, Mo is adjusting to her new low-paying job, her bisexual reawakening, and her new neighborhood’s wacky characters. There’s Claudia, an old woman who refuses to let Mo help her cross the street, and Marlowe, a tween cell phone prodigy whose antics terrify her. But Mo’s greatest nemesis is Poodle Dude, a guy with an SUV full of poodles who speeds through her intersection each morning. . . until the day he speeds into a sinkhole. Mo tries and fails to shield innocent eyes from his bloody corpse, but succeeds in accidentally becoming the guardian to his three poodles.

And that’s not the worst of some of the locals are convinced that Poodle Dude was murdered. Their allegations are obviously ridiculous, but Mo, desperate for distractions—and for several hot neighbor-suspects—reluctantly agrees to help. But Mo the detective is just as chaotic as Mo the underemployed adult, and the three entitled poodles are not helping. When a second local dies under mysterious circumstances, it’s going to take all of Mo’s broadly applicable and transferrable skills to find the killer.

Murderers beware. . . DON'T CROSS MO ELLERY!

Genres: Mystery, Fiction, Mystery Thriller, Queer

336 pages, Paperback

Expected publication August 11, 2026

About the author

Birdie Horne is the combined pen name of former enemies Eden Robins and MW Garguilo. Over the years, they have been love rivals, co-godmothers, and neighbors across an alley in Chicago. Separately, they have published over twenty books, and together they have a resume full of the kinds of jobs that genuinely worry their parents. DON'T CROSS MO ELLERY is their first outing as Birdie Horne.

Reviews

[Marcus Mitchell · Rating 4 out of 5]

This teeters around the 3.5 range but screw it, I'll go with a four. It was a fun read and one of the few books I read over the course of just 24 hours. You can tell the author duo had a great time writing this, from the "yes, and" style plotting to characters who are both a bit much and all too real at the same time. Marlowe is the highlight of a wonderful cast that really doesn't have too many weak links. I'm excited to go back and reread her and Tasha's introductions for a lesson in how to make characters so darn likable. The formatting and humor won't be for everyone I think, but it absolutely works once you let yourself take a backseat in Mo's head and just watch her wind-up toy herself around the outskirts of Chicago.

Mo is a whirlwind and it's nice to see a detective story with someone who just has no idea what she's doing. But she's figuring it out and that's the point. She chases down leads, walks into dangerous situations with unearned confidence, and throws accusations around with ease. The mystery itself isn't too complex (complimentary), but I will fully admit I gasped when a reveal happened.

Excellent pacing is the star of the show here. I don't think I've read a "self discovery" type of character arc that zips quite like this. Mo's motivations and feelings are stated clearly and no scene feels like its dragging on as she doomspirals and shushes her way through conversations. Having three large dogs dragging her around does wonders for keeping things moving.

The book gets off to a rough start I maybe wasn't ready for and there were initial worries that the book was going to be a little too "random lolz" for me to enjoy, but things thankfully settle into a nice rhythm. I'm glad I persevered through what was mostly a prologue and now I'm hoping there's a sequel in the future!

Thanks to NetGalley and the publisher for this advanced copy, I really enjoyed it.

[Bethany · Rating 4 out of 5]

“There’s a lesson in here somewhere for me. Not that I like getting my life lessons from murderers.”

This is a fun one, y’all.

Mo Ellery’s life implodes on her 29th birthday. She finds herself jobless, boyfriend-less, and apartment-less all on the same day, as everything goes south for her in a laugh-out-loud-funny sequence of events. (Not that I like to laugh at others’ misfortune but it is all quite comical.)

Fast forward and now Mo is living in a studio apartment, serving as a crossing guard—she’s a bit of a Google-assisted hypochondriac and needs those health benefits—and facing off against her speeding, poodle-dad nemesis every morning. Well, she’s facing off against him, that is, until he ends up dead, back wheels up in the massive sinkhole in front of his stalled parking garage development right next to her crossing guard corner.

Soon she finds herself holding the reins of three show poodles and inveigled into investigating a possible murder—neither of which she is entirely equipped to handle.

It’s a comedic, late coming-of-age tale, centered around the amateur detective antics of Mo and an increasingly kooky cast of characters, in which the chaotic bisexual FMC flails about as she seeks answers, stability, and love (or at least some more hookups) before she turns 30.

It is so much fun and is bound to make you grin, chuckle, and maybe even laugh out loud.

I received an advance copy of the book from William Morrow. All review opinions are my own. #MorrowPartner

[Sheila · Rating 3 out of 5]

I received a free copy of, Don't Cross Mo Ellery, by Birdie Horne, from the publisher and Netgalley in exchange for an honest review. Mo Ellery is starting her new calling as a crossing guard. Mo Ellery is not your typical crossing guard at all. This book was funny at times.