Karl Roebuck and Elise Wasserman renew their Anglo-French alliance when they investigate a dark crime that takes place on the murky waters of the Channel as a burning fishing boat turns into a new case for them.
As Karl and Elise continue their investigation a shocking discovery is made at an immigration removal centre, alongside a sinister animation that contains a hidden message.
The investigation takes a bizarre and troubling turn when Winnie is sent a box containing a live rat with a set of co-ordinates leading to the latest victim of the Pied Piper.