One morning, when Moominmama steps outside, she finds that a flying saucer has plowed up her vegetable garden. From the crash-landed UFO hangs a quirky machine that Moominpapa is eager to use to finally fix his broken radio. However, as he fiddles with it a bit, Moomin suddenly becomes invisible. And what about Papa? He does too! What a fantastic device! Every button on the machine triggers the most curious surprises! Until, at the thick end, the pilot of the UFO wants to join in as well. Help, Martian alert! Tove Jansson's Moomins have lost none of their magic and irresistible charm to this day.