Ruby's humdrum life is thrown upside down when she receives a text from her college sweetheart inviting her to drop everything and fulfill the pact they made 17 years previously.
From writer/producer Vicky Jones and Emmy®-winning executive producer Phoebe Waller-Bridge comes a new, wildly unconventional romantic-comedic-thriller about a woman, Ruby Richardson (Merritt Wever) who walks away from her ordinary life in the suburbs to revisit her past with her college boyfriend, Billy Johnson (Domhnall Gleeson), with whom she made a pact over 15 years ago that if either one of them texted the word “RUN” and the other replied with the same, they would drop everything and meet in Grand Central Station and travel across America together.
Seventeen years later, both Billy and Ruby have secrets they don’t want to reveal. Ruby has not become the successful architect Billy always thought she would, and is a wife and mother with no independent income, and Billy, though successful, hides secrets and insecurities of his own. Over the course of seven episodes, Ruby and Billy travel by train across the country from New York to Los Angeles and must decide what they want their lives to be and what they’re willing to give up in exchange. Can their new selves exist in their old lives, will they be able to leave their baggage behind, and what happens when the running ends?