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

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

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.

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.

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.

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

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.

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