Lysomnus needs Marcus's help more than ever. The planet's broken moon is falling out of orbit, threatening to end all life on impact. The answer to the problem is far away in Lysomnus's ocean - too far for even the mighty Stondefel to fly.
With the help of old friends and new friends, family and with new resources, Marcus, Sadie, and Leopold willl do everything they can to save the world tey have come to think of as home.