When an asteroid has an 84.7% chance of colliding with the Earth in four days, eleven-year-old Kemi, who loves scientific facts and probability, assembles a time capsule to capture her family's truth as she tries to come to terms with saying goodbye.

"When the world is ending, what matters most to you? Seventeen-year-old Aisha hasn't seen her sister June for two years. She has no idea where she is, but that hasn't stopped her from thinking about her every day and hoping she's okay. But now that a calamity is about to end the world in nine months' time, she and her mother decide that it's time to track her down and mend the hurts of the past. They don't have any time to spare - if they don't resolve...