Season 4 - Episode Guide

An attack forces an American submarine into a disastrous dive, and the crew struggles to regain control while battling a chemical fire that threatens their air supply.

The career of a young U-Boat officer begins with promise when he is awarded command of his own submarine, but clashes over Nazi ideology cause tension.

Documentary series exploring the use of submarines in the Second World War.

When Hitler sends U-Boats to protect his troops, a German sub rushes towards the fjords leading to Narvik - the scene of two major naval battles.

A new submarine commander must overcome dissent despite his unconventional choices. The crew works together to build trust as they travel dangerous Japanese home waters.

Documentary series exploring the use of submarines in the Second World War.