After Ed gives Christopher a bath, he tries to get Christopher some food, but Christopher won’t speak. Ed goes to do the laundry and Christopher does mental math to calm himself down. When Ed comes back and Christopher still isn’t speaking, Ed sits on the bed and tells him that he doesn’t tell the truth all the time, but he’s trying, and he’s going to tell the truth in the future. He’s learned that lying causes more hurt in the long run.
In a situation in which nothing seems to make sense, Christopher’s mental math brings him back to a logical place. Ed begins to face big questions about whether lies can ever be the best choice. He thought that lying about Judy would protect Christopher, but now he sees how much damage that lie has done to his son.
In order to keep this promise, Ed admits that he was the one who killed Wellington. Christopher wonders if he’s joking, but Ed goes on to explain. Mrs. Shears helped out a lot after Judy left, and Ed thought they might move in together. Then he and Mrs. Shears argued, and he got the impression that she cared more about Wellington than about him and Christopher. She kicked him out of her house, and Wellington was in the garden. He was very angry, and he imagined Wellington might attack him, so he killed the dog.
Ed immediately tells a truth to show that Christopher can trust him to be honest now. Ed also exposes a vulnerable side of himself with the story about Mrs. Shears, showing that he sought love and support and was rejected. At the same time, he exposes himself as having a temper and desperation strong enough to make him kill a dog, even though he told Judy off for these same qualities.
Christopher becomes frightened. Ed tries to touch his hand in their way that symbolizes hugging, but Christopher pushes him off the bed. Ed decides to let Christopher settle for the night, and goes downstairs. Christopher realizes he has to leave the house, because if his father killed Wellington, he might kill Christopher. He decides he can no longer trust Ed.
Christopher waits a couple of hours and then sneaks downstairs with his Swiss Army Knife. He finds Ed asleep in the living room. He brings Toby and some food and goes into the garden, where he hides behind the shed. He eats a snack and wonders what to do.
Christopher seriously believes himself to be in immediate danger, as proven by him clutching his knife. He shows his love of Toby in bringing him, too, out of the danger of his father’s presence.