Story : Natalie’s new boyfriend, Francois, is keen to become involved in Lifeline, but Albert has doubts. Paul Vercors, the fanatical leader of a Communist cell in Brussels, wants to take over Lifeline, and tries to enlist the assistance of a colleague – Max. Meanwhile, the Communists continue their resistance activities and plant explosives on a railway line to derail a train. Unfortunately, the train’s passengers include Natalie and Francois, escorting evaders down the line.