Operation: Silent Angel

by Margaret Kay

A love ignited two decades ago, a desire that would not be extinguished, but happily ever after was not something people in their line of work were granted. The mission was too important.
Yvette 'Control' Donaldson is every Operator's rock. Her voice is their lifeline. She has their backs, and they trust her and follow her direction without question when they are in a hostile land, and all hell has hit the fan.

But who has her back when she needs someone?

this story is realistic, with adult language and content on the way to the HEA. This is book 18 in the Shepherd Security series. Even though the story does continue from book to book, each is a stand-alone story and can be read without reading the prior book(s), but they are best enjoyed in order.

416 pages, Kindle Edition

Published October 15, 2025

About the author

Margaret Kay is a wife, a mother of two adult children, a grandmother, a pet lover who makes her own dog food from scratch, and a writer of Military Romance Novels.

Margaret's husband proudly served 8 years in the United States Navy. She's a veteran of more than a few deployments as the spouse who took care of the family while her military member served halfway around the world.

Reviews

[Ms Tracy · Rating 3 out of 5]

Not her best writing

I've loved every Shepherd Security book up until this one. This one feels like a total afterthought. The amount of unnecessary words truly made me feel like the word count of the actual story weren't enough so extra words were added. Things like saying someone is exhausted & knew they would fall right to sleep, then saying they layed down. Then they slept??? This is not Ms Kay's normal great level of writing. whole book read like something thrown together, words added to make it long enough. Yvette's character 'Control' deserved better

[Angela · Rating 5 out of 5]

A definite must read book and series

This is another one of my favorite series, and the stories just keep getting better and better. I love what Shepherd Security stands for, what/who they fight for, and how they have become a huge loving and loyal family. If only there were many more unselfish people our world.
I can't wait to read more of this series!
I would definitely recommend this book, series, and exceptional author.

[Mrs · Rating 2 out of 5]

No real grip

This book was written in a completely different style from the author’s previous works. Unfortunately, I found myself skimming through large portions because it didn’t hold my interest and felt padded with unnecessary content. I was looking forward for Yvett and Mac’s story, but it lacked the emotion, depth and connectivity I was hoping for. I truly hope this isn’t the direction Margaret Kay plans to take in her future books.

[Nancy · Rating 5 out of 5]

Silent Angel by Margaret Kay

This book is Mac and Yvette’s story. They met many years ago and have loved each other just as long but with their careers they only got together for short times. Their careers were not compatible for them to be together. Now is the right time for them to stay together. Wonderful book.

[Jackee Jolly · Rating 5 out of 5]

great. story

As usual this was another wonderful correlation of all the great members of Shepherd Security and their lives.
Mac and Yvette are a treat and the longevity of their relationship is very evident amongst the action and mystery of this book.
Can’t wait to see Shepard and Dianna as parents, hopefully in the next adventure at Shepherd Security

[Abby · Rating 2 out of 5]

My rating: 2 stars. I have loved this series from the beginning. … but unfortunately, it’s run its course and it doesn’t have the wow factor for me anymore.

This was Mac and Yvette’s story … but, then it wasn’t! I found the two other storylines took away from the main character story. The author could’ve run with the original storyline and expanded it.

[Kevin · Rating 5 out of 5]

Another great Shepard Security story! Love Yvette and Mac.

Loved how Mac and Yvette is love story was interwoven within the mission they both go on! It was wonderful seeing Mac's growth and how he fit in this the different Shepard teams. Love this book!!! Wish I could have given it more than 5 stars!! 💥💜🌟📚🔥😺

[Debbie Hargis · Rating 5 out of 5]

Loved this one!!

Something I hope would happen has now become a possibility. Diana’s pregnant!! Can’t wait to find out when they announce it and the baby is born. Good story of Michaela and the ma she’s been involved with for two decades.

[Fran · Rating 5 out of 5]

Shepherd Security book 18

Another awesome book . I hope they are going to continue the series. I would like to know what to the rest them . and to know what Diana and Shepherd baby is boy or girl?

[Ann Marie Wells · Rating 5 out of 5]

Amazing

Hooks you right in with twists and turns and keeps you wanting more - oh the cliff hanger can't wait for the next book

[Tom Prejsner · Rating 5 out of 5]

Romance

Thank you for sharing these wonderful romance novel series books. Please keep writing more of these wonderful books. Thank you

[Beth Jones · Rating 5 out of 5]

Great read

This book is a romantic suspense novel about Seth "Mac" Makris and Yvette "Control" Donaldson getting together with each other. This book is a great story. HEA

[Susan · Rating 3 out of 5]

I loved the other books in this series. This one just wasn't for me.

[MaryAlice Goss · Rating 5 out of 5]

Absolutely loved this book!!! Can't wait for the next book in the series. Hope we find out more about Sheppherds baby!!

[CHANDRA RENEA FIELDS · Rating 5 out of 5]

Chandra's Review

I truly enjoyed reading this book it was intriguing, mysterious, loving,and full of action! I would definitely recommend this book to read! 🤗🤗👏🏾👏🏾

[Melinda · Rating 3 out of 5]

I love these books, but mafia stories are not for me.