Ali isn’t like her sister, Julia. She keeps to herself on the Lunar Colony where they live with their parents. But when Julia offers her an opportunity to buy apples, a rarity on the moon, she goes along, enticed by the idea of seeing Kofi, whom she’s had a crush on for ages. When some of the kids decide to mess around with an airlock’s controls, it’s up to Ali to figure out a solution. Will she be able to save the kids before time runs out?