The clock rolls back to the first days aboard Fulmar's Folly. Adrift in a nautical apocalypse; Jack and Sam attempt to shield the children... as the world slowly eats itself alive. In the present day: Something’s clearly wrong with Arrietty.

Picking up straight where season one left off: Lina is furious to discover she's risked everything on a boat stuck at anchor and void of supplies. With dwindling water and plenty of injuries, a traumatised Arrietty is faced with the reality of killing Jimmy. All the while a new adversary is...