Countdown Zero (Agent Zero Spy Thriller #18)

Countdown Zero (Agent Zero Spy Thriller #18) by Jack Mars is out now, published January 24, 2026.

See if this book is on Audible (Free Trial)

Countdown Zero (Agent Zero Spy Thriller #18)
Check availability on Amazon
As an Amazon Associate we may earn from qualifying purchases, at no extra cost to you.
Countdown Zero (Agent Zero Spy Thriller #18) Release Date: January 24, 2026

Published

‘You will not sleep until you are finished with AGENT ZERO. A superb job creating a set of characters who are fully developed and very much enjoyable. The description of the action scenes transport us into a reality that is almost like sitting in a movie theater with surround sound and 3D (it would make an incredible Hollywood movie). I can hardly wait for the sequel.’
–Roberto Mattos, Books and Movie Reviews

COUNTDOWN ZERO is book #18 in the #1 bestselling AGENT ZERO series, from #1 bestselling and USA Today bestselling author Jack Mars (with over 10,000 five-star reviews). The series begins with AGENT ZERO (Book #1), a free download.

Beneath the ocean’s surface lurks a submarine gone rogue, threatening coastal chaos with hypersonic missiles unless their ransom demands are met.

With only 24 hours to halt the countdown to devastation, Agent Zero must navigate a deadly game of cat and mouse beneath the waves—a game where one wrong move could lead to catastrophic consequences.

The AGENT ZERO saga offers a gripping journey packed with unexpected turns and dynamic action, keeping you enthralled from start to finish. At the core of this thrilling series is an engrossing relationship between a father and his daughter, which is sure to keep you reading voraciously until the early hours.

Books #19–#24 in the series are also available!

‘Thriller writing at its best.’
–Midwest Book Review (Any Means Necessary)
⭐⭐⭐⭐⭐

‘Thriller enthusiasts who relish the precise execution of an international thriller, but who seek the psychological depth and believability of a protagonist who simultaneously fields professional and personal life challenges, will find this a gripping story that’s hard to put down.’
–Midwest Book Review, Diane Donovan (regarding Any Means Necessary)
⭐⭐⭐⭐⭐

‘One of the best thrillers I have read this year. The plot is intelligent and will keep you hooked from the beginning. The author did a superb job creating a set of characters who are fully developed and very much enjoyable. I can hardly wait for the sequel.’
–Books and Movie Reviews, Roberto Mattos (re Any Means Necessary)
⭐⭐⭐⭐⭐

Reader Anticipation Rating:
[Average Rating: 4]

Book Club Journal: Reading Log For Adults & Kids Who Love Books!
Book Club Journal: Reading Log For Adults & Kids Who Love Books!
Check Latest Price
We earn a commission if you make a purchase, at no additional cost to you.

Genre: Thriller

Jack Mars

More books from Jack Mars

🎧 While You Wait for Countdown Zero (Agent Zero Spy Thriller #18)

Prefer audiobooks?

Check Audible to see if Countdown Zero (Agent Zero Spy Thriller #18) is available to listen to.

Start a free trial and get your first audiobook free.

✔ Listen while commuting or relaxing
✔ Your first audiobook is free with the trial
✔ Cancel anytime

Start Audible Free Trial

Book Club Journal: Reading Log For Adults & Kids Who Love Books!
Book Club Journal: Reading Log For Adults & Kids Who Love Books!
Check Latest Price
We earn a commission if you make a purchase, at no additional cost to you.

Recommended Book Release Guides

Similar Books Liked By Our Readers

Leave a Reply

Your email address will not be published. Required fields are marked *