Conor O'Malley is a thirteen-year-old boy who lives with his mother. She's very ill and undergoing treatment for cancer. Every night, seven minutes after mdnight, a monster pays a visit to Conor. He's going to tell him three stories, and then Conor will have to tell a story of his own.
This is an emotional, gut-wrenching story. Conor has to face not only his mother's illness, but also being bullied and having to life with his grandmother, whom he doesn't like. He also has nightmares, compared to which the monster's visits are not really scary for him. What's frightnening is the monster's request: he wants the truth from Conor, the truth about his nightmares.
This is a short book, yet very powerful. I'd totally recommend it.