Futaba is a girl who was in love with a boy named Kō Tanaka in middle school. However, after a misunderstanding, their relationship as friends ends when he transfers schools over summer vacation. In high school, her world is turned around once again when she meets Kō again, this time under the name of Kō Mabuchi.
Sawako Kuronuma's one wish in life is to make friends. That's a difficult proposition when everyone who meets her cowers in terror, due to her resemblance to Sadako (after whom they nickname her) from the Japanese horror movie series The Ring. Shunned by her classmates, her life starts to change after she befriends her classmate, Shōta Kazehaya, a popular, easygoing and 100% refreshing guy who is nice with everyone, even with her.
Oz Vessalius, heir to one of the duke houses, has just turned fifteen. His life is rich and carefree, darkened only by the constant absence of his father. At his coming-of-age ceremony, however, everything changes. For no reason that he can discern, he's cast into the prison known as the "Abyss", only to be saved by a "chain" known as Alice, the bloodstained black rabbit. It is unknown why was he cast into Abyss, how does Alice factor into it all, and what does the organization known as "Pandora" want with him.
Despite Ryuji Takasu's gentle personality, his eyes make him look like an intimidating delinquent. Class rearrangements on his second high school year put him together with his best friend, Yusaku Kitamura, and his hidden crush, Minori Kushieda. Along with these two comes Kushieda's best friend, Taiga Aisaka. Her delicate appearance contrasts with her brutal personality. Secretly in love with Kitamura, Taiga agrees to help Ryuji with his love interest as long as he helps her get closer to hers.