Josh has always called his brain Brian, and Brian can sometimes be his best friend, helping Josh with tests and giving him brilliant moneymaking ideas. But he can also be Josh's worst enemy, keeping him awake at night worrying, and telling him that his family's problems are all Josh's fault. When the arguments at home get really bad, Josh is sent to live with his grandma, who lives in a weird shack in the middle of nowhere. At first Brian's voice gets louder and louder, and Josh feels out of control. But as he helps his grandma in the garden, growing their own food, and with all the jobs that need to be done around the shack, Josh starts to realise that she understands him and Brian better than anyone.