During a family trip on an airplane, Hari and Duri, along with the guardian spirits Simbi and Gimbi of the Mysterious Apartment, rescue the fallen sky spirit Prince Jubi. However, they accidentally summon other unknown monsters to attack. But the greatest crisis is the awakening of the legendary flying giant beast, Jörmungandr. Hari's exorcist friend, Kangrim, is summoned to help. In its fierce assault to seize the sky spirits, Jörmungandr puts the human world in grave danger. With the Ghost Sphere and the Sky Barrier, these little heroes must ascend to the highest clouds to prevent the destruction of this city—and even the Earth... This October, the most thrilling adventure is about to unfold. Summon your courage and fight for the ones you love!