Red Night Eve

A high-school student known for being the most attractive girl in school, Hana, experiences a supernatural occurrence during a beach outing with friends. The event, referred to as a "Red Night Eve," involves a colossal shark that attacks her while swimming. She is saved by two classmates, Yayako and Yuuto Kagimori, who are familiar with such incidents and use a support AI named Acacia on their tablet. Soon after, Hana and the siblings encounter another supernatural event involving her class pet parakeet, which becomes monstrous. These events drastically alter the course of Hana's life.