Steve Backshall travels to the tropical islands of the Bahamas for an underwater mission like no other. Using the latest Deadly time-slice technology Steve reveals the science of a shark bite when he dives amongst dozens of hungry lemon sharks. Beneath the waves he and the crew then have a hair-raising encounter when the Bahamas largest and most feared predator, the tiger shark, becomes a little too inquisitive. Finally, back on the mainland, deep underground, Steve faces one of his innermost fears as he enters one of the deadliest environments on the planet - a complex flooded cave system. Getting lost and running out of air is Steve's worst nightmare.