Another school partnered with Kokoro's school to organize a bazaar where gently used household items could be sold or given away. On their way home, Kokoro's friend Tama Elder revealed that she and her Cocotama companions had won a trip to Cocotama World where they witnessed the mighty Cocotama gods. Elder Tama urged Kokoro to teach humans about the significance of their belongings rather than abandoning them recklessly. Unfortunately, Tepple intruded into the Cocotama World and stole a critical acorn that transformed discarded objects into mushroom-producing sources of negative energy, affecting both humans and Cocotama. The Cocotama group attempted to locate the misplaced acorn to restore balance, but their endeavors proved fruitless since humans persistently discarded it. Tepple exploited the acorn to acquire a Happy Star, which darkened the Cocotama World and gave rise to more mushrooms. The Happy Stars infiltrated the human world, draining its enchantment. Kokoro and the Cocotama worked to soothe Tepple's heart and prevent the darkness from enveloping the human world.