Commander Elise Wassermann and DCI Karl Roebuck reunite to investigate the case of a French couple who are abducted from the Eurotunnel. But the case is complicated when a plane crashes into the Channel, hugging all on board.

Karl and Elise continue to work on the case.

Discovering the Fourniers becomes a matter of national urgency after the crashed plane's black box reveals a shocking possibility.

Karl and Elise get a tip-off from a woman they think knows Robert Fournier's whereabouts.

An unexpected revelation could end up turning Karl's life upside-down. Eryka reaches out to Elise whilst Rosa offers the team a cryptic clue.

An anonymous package offers Karl with his biggest breakthrough in the case yet. The team receive a clear and unhappy warning.

The team end up having to make a deal with Vanessa. Somebody attempts to warn Karl off the case whilst Elise crosses a line she could quickly come to regret.

A lethal attack gets underway and Elise and Karl's lives end up being thrown into jeopardy.