One day Christopher found Mrs Shear's dog dead in her garden.
The police took him to the police station where his father came to pick him up.
Christopher decided to do some detective work and talked to lots of people, including Mrs Alexander who told him that his father didn't like Mr Shears because he had had an affair with Christopher's mother.
Christopher's father didn't like his detective work so they had a huge fight. (couldn't find a punch anywhere so used my imagination.)
After Christopher magically survived the fight he saw some letters in his dad's cupboard.
They said that his mother was alive! Christopher was very scared by this.