Summary from Goodreads:
When eleven-year-old Annie first started lying to her social worker, she had been taught by an expert: Gran. "If you’re going to do something, make sure you do it with excellence," Gran would say. That was when Gran was feeling talkative, and not brooding for days in her room — like she did after telling Annie and her little brother, Rew, the one thing they know about their father: that he was killed in a fight with an angry man who was sent away.
Annie tells stories, too, as she and Rew laze under the birches and oaks of Zebra Forest — stories about their father the pirate, or pilot, or secret agent. But then something shocking happens to unravel all their stories: a rattling at the back door, an escapee from the prison holding them hostage in their own home, four lives that will never be the same.