The team persuades The Gas Man to step out from the shadows. He reveals the first big clue in the investigation to how he got away with it – and makes a surprising claim about his role in the case.

Chloe makes a startling discovery about another chemical trafficker that has consequences for her investigation. A Kurdish survivor of mustard gas shares her story

In this episode, Chloe looks into what happened to The Gas Man when he arrived back in Germany as a fugitive – and investigates whether his trade with Iran ever really ended