When Tom's girlfriend walks out on him the day before Christmas, he feels humiliated but not necessarily heartbroken. Sadie wasn't, after all, The One. If we're being precise, she was number 85. And so, for reasons that are only mostly wrong, Tom embarks on a mission to bring his number of encounters up to a nice neat 100. Over the course of his quest he sleeps with a colleague, a colleague of a friend, a friend of a friend, a friend of a friend's wife, the estate agent selling his flat, and several more besides. Everything is going, if not well, then at least according to plan ... and then Tom meets Verity. Whether she's The One remains to be seen, but she's certainly more than just another number.