You're feeling pretty smug about your commute to work by riverboat. No more traffic gridlock or getting stuck on the tube in tunnels (you're claustrophobic). Now you've got fresh air, an iconic Thames view, a whole lifestyle upgrade. You've made new friends on board - led by your hedonistic young neighbour, Kit - and just had your first official 'water rats' get-together.The day after the drinks, Kit isn't on the morning boat. The river landmarks are all the same, but something's off. When you disembark, the police are waiting. Kit's wife, Melia, has reported him missing and another passenger saw you arguing on the last boat home after your drinks. Police say you had a reason to lash out at him. To threaten him.You protest. You and Kit are friends - ask Melia, she'll vouch for you. And who exactly is pointing the finger? What do they know about your private lives?No, whatever coincidences might have occurred last night, you are innocent, totally innocent.Aren't you?