When Jonah and Raff wake up on Monday, their mother Lucy isn't there. Although Jonah is only nine, he is the big brother, and knows enough about the world to keep her absence a secret. If anyone found out she'd left them alone, it could be disastrous for him and Raff; and she'll be back, he's nearly sure. With growing unease, he puzzles over the clues she's left behind. Who sent her the flowers? Why are all her shoes still in the house? Why is her phone buried in a plant pot? And who, in their diverse south London community, might know more about her than he does?