Nikki and the Lyell team continue to investigate the plane crash, ruling out an explosion and engine failure. Suspicion turns to Rowan Cole, the so-called Deadhead - a non-flying pilot who was hitching a lift back when his intended flight was cancelled. The investigation takes a turn when they discover a connection to a sinister online forum. Nikki’s partner Matt is grieving following the death of his close friend, putting their relationship under strain.