Stephen Dillane and Clémence Poésy reprise their roles in the second series of this British/French crime drama. When a French couple go missing after boarding the Eurotunnel, all that remains is their young, traumatised daughter. As DCI Roebuck (Dillane) and newly-promoted Commander Wasserman (Poésy) team up to investigate the mystery, a plane crashes into the Channel killing everyone on board. With more questions than answers, Roebuck and Wasserman begin to wonder if there is something bigger at play...