The book opens in summer 1939 with Ada, the narrator, sitting at the window of her family’s one-room flat in London. Her mother, Mam, is abusive and keeps Ada isolated in the third-story flat. Mam is ashamed of Ada for being crippled by a clubfoot. Ada doesn’t know that her condition is called clubfoot and knows only that she has a bad foot, which she believes is her own fault and the reason for Mam’s physical and verbal abuse.

Ada is afraid of being alone and struggles when her younger brother, Jamie, begins making friends and staying away from home more frequently. At one point, she ties him up to prevent him from leaving but realizes that doing so makes her like Mam. Ada and Jamie’s ages aren’t certain, but Mam says Jamie is six years old and will start school in the fall. Jamie attending school means he’ll be gone even more, so Ada decides to teach herself how to walk.

Ada teaches herself how to walk while she’s home alone. She falls constantly, making it a painful and bloody experience, but Ada is persistent. She imagines gaining Mam’s acceptance, going shopping, and going to school, all because she can walk.