The new arrivals on board from the Kinloch Charlie immediately make their presence felt, as Pictor head Coake enlists a group to undermine a weakened Magnus and force their way to the pump control. But when Coake's motives are investigated and the crew realise he isn't giving them the full truth, they find themselves locked in an urgent race for answers with lives at stake.

Scores are settled and mysteries revealed as Coake is pushed to explain Pictor’s plan and the true reason for his mission onboard, Rose and Fulmer work out the horrifying extent of what the coded messages they have discovered really mean, and Magnus must put his personal demons to rest and lead the crew in one final bid for their survival.