This romantic comedy by writer-director Peter Howitt is built around the intriguing narrative premise of exploring all the things that might have ensued if a young woman in London (Gwyneth Paltrow) who’s just lost her job at a PR firm hadn’t missed her train. Through parallel editing that Howitt makes surprisingly easy to follow, two disparate story lines unfold in parallel universes. Unfortunately, once the freshness of the concept wears off, the same premise starts to feel mechanical and willful. With John Hannah, John Lynch, Jeanne Tripplehorn, and Zara Turner. (JR)