Sara's little brother is born premature. He looks small and red, like a baby bird, so she calls him Birdy. Because she can't visit him often, she writes him letters about everything that's happened since he's been born--like how her mom and stepdad are sending her to Toronto to stay with her half-sister, Abby. And how Abby lives in this amazing storage container house on a vacant lot and hopes to build a whole community of them for unhoused people. Sara discovers she too has ways of getting things done--like passing the librarian a note asking for books instead of saying it out loud, or talking to the dogs at the homeless encampment as a way of meeting their people. When she sees that the mayor and the police are making things harder for the unhoused community, Sara realizes she can be an advocate--through her letters--and that there's more than one way to stand up for what you believe in and make your voice heard.