'How cool was Will Freeman?' Too cool! At thirty-six, he's as hip as a teenager. He's single, child-free, goes to the right clubs and knows which trainers to wear. He's also found a great way to score with women: attend single parents' groups full of available (and grateful) mothers, all hoping to meet a Nice Guy.

Which is how Will meets Marcus, the oldest twelve-year-old on the planet. Marcus is a bit strange: he listens to Joni Mitchell and Mozart, looks after his mum and has never owned a pair of trainers. But Marcus latches on to Will - and won't let go. Can Will teach Marcus how to grow up cool? And can Marcus help Will just to grow up?