In 1990, three boys are born, unrelated but intertwined by circumstance: Dayo, Iseul and Youssef. They are adopted as infants and live in a shared bedroom perched atop a mosque in Staten Island. The boys are a conspicuous trio: Dayo is of Nigerian origin, Iseul is Korean and Youssef indeterminately Middle Eastern, but they are so close as to be almost inseparable. Nevertheless, Youssef is keeping a secret from his brothers: he has an imaginary double, a familiar who seems absolutely real, a shapeshifting creature he calls Brother. The boys' adoptive father, Imam Salim, is known for his radical sermons extolling the virtues of opting out of Western ideologies. But he is uncharismatic at home, a distant father who spends evenings writing letters to his former compatriots back in Saudi Arabia. When Imam Salim's path takes him back to Saudi Arabia, the boys will be forced to follow.