It's the off-season at the lonely Beauregard Hotel in Bournemoth, and only the long-term tenants are still in residence. Life is stirred up, however, when the beautiful Ann Shankland arrives to see her alcoholic ex-husband, John Malcolm, who is secretly engaged to Pat Cooper, the woman who runs the hotel. Meanwhile, snobbish Mrs Railton-Bell discovers that the kindly if rather doddering Major Pollock, played by David Niven, who won an Oscar for his performance, a retired officer who likes to find out more...

A bomber who has just destroyed a train plans to kill thousands more with a much larger detonator in the heart of Chicago within hours. A top-secret program allows an initially mystified Captain Colter Stevens to exist briefly as another man in the parallel reality of the doomed commuter train. Each time he returns to the train, Colter has just eight minutes to uncover the bomber’s identity. The more he learns, the more convinced the soldier becomes that he can prevent the deadly blast from ever find out more...