The story goes back to the beginning at the Belfast shipyard where political strife is interfering with the ship's construction. The designer offers electrical engineer Jim Maloney steerage passage on the liner if he and his team manage to get the wiring finished on time. The following month as the passengers board the ship Jim meets a passenger who leaves his wife feeling unsettled. In second class, Muriel Batley resents her husband John's fawning to the Earl and admits that she knows a secret about his employer.

Cast: Ben Bishop, Glen Blackhall, Ruth Bradley, Dragos Bucur, David Calder, Stephen Campbell Moore, Jenna-Louise Coleman, Lloyd Hutchinson, Celia Imrie, Ralph Ineson, Mark Lewis Jones, Toby Jones, Will Keen, Grainne Keenan, Maria Doyle Kennedy