Apples on the Moon

Ali isn't like her sister, Julia. She keeps to herself on the Lunar Colony where they live. But when Julia offers her a chance to buy apples, a rarity on the moon, she goes along, enticed by the idea of seeing her cute classmate Kofi. 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 in time?