Fergus Frew thought he knew what to expect when he signed up with the Navy's demolitions team. But as the Korean War rages on, Fergus and his fellow divers -- a.k.a. "frogmen" -- are tasked with more than just scouting mudflats. Soon they're planting mines. And sabotaging tunnels, bridges... and even fishing nets. Scariest of all, it falls to Fergus to discover where the enemy has placed their mines, a job as painstaking as it is dangerous.