An inexperienced U-boat crew are plunged into a perilous secret mission, while new translator Simone starts work at the base.

Hoffmann insists on further training despite the crew's desire to head to battle. In La Rochelle, Simone pieces together the previous night's events.

Tennstedt and Hoffmann continue to butt heads aboard U-612, while rebel Carla Monroe plans a mission in La Rochelle.

Unity on U-612 has crumbled and Hoffman and Tennstedt's continued conflict could jeopardise the mission. On land, Simone wrestles with a difficult choice.

A surprise new arrival takes Greenwood's place, causing a divide. Plus, Carla and Simone grow closer and a resistance fighter arrives at the safe house.

Things look bleak for the crew of U-612, as they desperately try to work out their next move. Simone adjusts to her new position between Carla and Forster.

Forster reveals to Simone that U-612 has gone missing. Meanwhile, the resistance endanger the innocent to further their cause.

The U-boat crew struggle with recent events and what lies ahead. A revelation in La Rochelle infuriates Forster spelling bad news for Simone.

Hoffmann struggles to hang on as his chance to escape heads toward US shores. Margot pushes on with her plans.

When Johannes' plan emerges, Gluck knows only one man is capable of stopping him. Margot needs help to get the Goldblatts out.

Tensions build beneath the ocean as Wrangel continues his pursuit of U-822. In New York, Sam takes drastic measures.

An attempt to get his crew on side has serious consequences for Johannes. Margot finds a vital ally as Forster reaches St. Remy.

Keen to impress his superiors, Forster cracks down on Anatole's wayward behaviour. Wrangel finally has his arch rival in sight.

Johannes and Wrangel try to bring their crews into line. Despite his growing love for Cassandra, Hoffmann seeks an escape route.

Wrangel catches up with Johannes, leading to a dramatic showdown out in the Atlantic. Hoffmann shows up at Cassandra's place.

Hoffmann struggles to hang on as his chance to escape heads toward US shores. Margot pushes on with her plans.