British and French detectives are brought together when a body is found inside the Channel Tunnel.

While the killer's second 'truth' unfolds, Stephen Beaumont crosses the paths of Karl and Elise once more.

The police face a race against time to identify and capture the killer as he steps up his campaign, targeting a further elderly victim in his 'moral' crusade.

Karl and Elise battle to locate an elderly soldier before he freezes to death at the hands of the killer. Meanwhile, runaway teen Sophie puts her trust in Benji.

The Truth Terrorist's third truth begins as Benji carries out his Samurai mission. The police hope to use teenage runaway Sophie to help trap the killer.

As the killer's incendiary fourth truth begins, Karl and Elise's suspicions fall on Stephen Beaumont. A manhunt begins, but is he the correct suspect?