Writer Tess has always been accused of being overly romantic by her best friend Carys.

And when they meet cheerful stranger Spencer and his more reserved wingman Ryan on the sleeper train to a wedding, Carys is all-in with the shared champagne while Tess holds back. Yet there's a jolt of attraction between her and Ryan that Tess can't ignore - a sense of recognition that feels real.

As the weekend unfolds, with a twist that nobody saw coming, she asks herself - how do you know when it's your life-changing moment?