Richard's (Eddie Marsan) wife Cath (Jessica Hynes) dumps him because of his passion for historical re-enactments -- in other words, because he wears homemade armor and runs around in the forest with other wannabe Vikings. Richard hopes to win back Cath and prove a hero to his bullied son, Martin (Joseph Hamilton), but all he's got is a hopeless Trekkie friend (Ewen Bremner) to help him discover his path back to adulthood.