You never forget the one that got away... Nell Mason is extremely happy with her life -- or at least, that's what she tells herself. She's lucky to have a high-powered job as a lawyer, even if it does come with an eccentric set of billionaire divorce clients. And she's absolutely fine living with her sweet, if slightly dull, boyfriend Gus in their London flat, where they have very sensible sex once (OK, sometimes twice) a week. She's definitely not stuck in a rut. But when Nell bumps into childhood friend and first love Arthur Drummond who broke her heart fifteen years ago, she's more than a little shaken. The seemingly perfect life she's worked so hard for starts to feel, well, less perfect.