On Valentine's Day, Hannah ends up in an Uber/car share driven by Finn. When Hannah loses her phone and they search for it, they also discover a box with an engagement ring that someone has dropped in the car. Hannah convinces Finn that they must find the owner, who is probably planning to propose on this very day (Valentine's). Finn lets himself be persuaded, and they embark on an odyssey through New York with the goal of saving the engagement. It turns into an eventful evening where they experience quite a lot together.
This movie doesn't quite hold up. Doing everything they do during this evening in New York would take several days, while in the film it's supposed to be maybe 3–4 hours. And then I wonder why Finn is sitting in a red car on the movie poster when he drives a black car in the film.