On a trip, Marsu eats a lot of round fruits in a clearing. When he gets home, he reacts with panicky horror to everything that is round. It takes a while for Hector and Aunt Diana to figure out what triggers his seizures. When they realize he has a "rundophobia," they clear away anything that's round, but also there are enough things in nature that are round and Marsu lives in fear and terror all the time. His family is not at all happy about him because he is no longer able to provide for them. Hector tries in vain to help him. Then at some point he comes up with the idea of going there with Marsu where it all started.