Deep Waters by H.I. Larry

Mission: Locate Secret Enemy Submarine
Enemy: Captain Stewart
Featured Gadget: Amphibious Submersible
Danger Rating: 3.7
 
Zac Power is about to embark on his first solo mission—finally! And it’s almost as cool as playing a guitar solo for millions of screaming fans. For years, top-secret government info has been stored at the bottom of the deepest ocean in the world. And it’s been totally safe…until now. The enemy is testing a new submarine that can dive deeper than ever before.
 
Can Zac find the enemy, protect the top-secret info, and still make it home in time to walk the dog?
 
- Goodreads Summary