Peso Penguin, the Octopod's medic, is returning a recovering sea cucumber to her home when his ship, the GUP-E, runs into trouble and the only creature he can see is a scary-looking fish.

When Aster wakes alone on a tropical island, she has no idea what's happened, why she's there, or where to find her younger sister, Poppy. Her last memories are blurred. All she can remember is being on a boat with her aunt and other members of the ecovillage where she was sent to live after the death of her mother. But Sam, who once met the sisters on a plane, makes links between the mystery of their disappearance and suspicious happenings in his...