One morning, on arrival at her PR company, Helen (Gwyneth Paltrow) finds out that she has just been sacked. She's on her way home and then she misses the tube train.
But what if she made it? She meets James (John Hannah) on the train, who's sitting right next to her and who's a friendly and witty man. When Helen gets home, she sees her boyfriend, Gerry (John Lynch) in bed with his ex-girlfriend, Lydia (Jeanne Tripplehorn) and Helen quickly ends her relationship with Gerry and forms a new, loving one with James.
The other possibility is that, Helen misses the train, gets robbed and a nasty cut, goes to hospital and by the time she arrives at home Gerry is already in the shower. Helen then gets a sandwich job and a waitressing job in order to support her loser boyfriend who is supposed to be writing his first novel but in fact has been cheating on her.
As the ending approaches, the story becomes unpredictable and it leaves you wonder why it has to go this way. The ending is likewise enigmatic. Heartily recommended.