Now, twenty years on, the Medusa is coming home. And, when a member of the team being sent to the drifting ship dies suspiciously, Bernice Summerfield is called up as a last-minute replacement. Something terrible happens on the vessel, and she and the rest of the eccentric team must use all their skills to solve the Medusa's riddle and understand the dark threat beneath. 

To do so, Benny must first understand herself and her colleagues - they are linked somehow to the original crew - and their fate. But as ghosts stalk the lonely corridors of the ship, the past is catching up with them in more ways than one ...