The Serpo Incident

Momo and Okarun meet while investigating the initial mysterious UFO sighting that sets the series' supernatural mystery in motion.

The series begins with Momo, a delinquent high school girl, investigating paranormal phenomena including a mysterious UFO sighting near Serpo. Her confidence and practical approach to supernatural investigation contrast with conventional attitude dismissing such phenomena as superstition. Okarun, whom she initially dismisses as stereotypical otaku nerd, interrupts her investigation while pursuing his own research into the same phenomena. Rather than becoming rivals, they reluctantly acknowledge their mutual interest and begin investigating together. The initial encounter establishes their dynamic: Momo's practical courage combined with Okarun's extensive knowledge creates complementary partnership. Momo provides physical bravery and social confidence while Okarun contributes research capability and understanding of supernatural phenomena. Their different temperaments create both friction and synergy as they investigate together. The Serpo incident introduces alien entities that become recurring threat, suggesting larger supernatural forces at work. By arc's end, Momo and Okarun have achieved their first significant collaborative success. They have genuinely helped each other—Momo has become more open to research-based understanding, and Okarun has become braver through Momo's example. Their developing partnership demonstrates that genuine connection emerges through shared purpose and mutual respect. The arc establishes foundation for their expanding investigation and deepening relationship.