Before We Go
Nick (Chris Evans) meets Brooke (Alice Eve) at Grand Central Station as Brooke misses her train home. He keeps her company until the next train tomorrow morning.
As it turns out, Brooke is married, but found proof of her husband cheating on her. While her husband went on a business trip and she went to New York, she left a letter on their bed telling him that it's over.
Brooke changed her mind about leaving her husband and wanted to get home to get rid of the letter before he found it. By missing the train, she didn't beat him home.
Nick and Brooke spend a perfect night together in a hotel room, after which Nick convinces Brooke to go home and patch things up with her husband. They share a tearful goodbye at Grand Central Station, but as Brooke gets on the train, she finds a comment card from the hotel in her pocket. There's something written on the back, which the audience doesn't see, but Brooke smiles when she sees it.