Takao Kasuga, a high school student fascinated by poetry, reveres Charles Baudelaire and even decorates his room with the poet's portrait. On a normal day, Takao forgets his copy of The Flowers of Evil in the classroom. When returning to retrieve it, he steals the sports garments of Nanako Saeki—a model student who Takao calls his muse and a femme fatale. Deeply ashamed of his act which he sees as a sin and what others see as a crime, Takao realizes with horror that Sawa Nakamura, his classmate and social outcast, knows about his theft. Blackmailed by her, Takao is now forced to partake in Sawa's disturbing fantasies, lest she reveals his deeds to everyone. Caught in a negative spiral of increasingly traumatic experiences, will Takao be able to break free from Sawa's thorns and atone for his sins?

Despite his incredible bashfulness, Atsuhiro Akkun Kagari has landed the girl of his dreams: the sweet and loveable Non Katagiri. However, his embarrassment for affectionate acts—from giving compliments to exchanging a kiss—causes him to act harsh and downright mean to Katagiri in their day-to-day lives. But Akkun is still very much a boy in love; he shows his admiration for Katagiri in his own way. From tailing her in order to take her picture to eavesdropping in on her conversations, he ends up stalking his own girlfriend. Luckily enough, Katagiri finds Akkun's actions cute and endearing, and knows he doesn't really mean any of his insults. Even if their close friend, Masago Matsuo, finds their dynamic a little odd, Katagiri loves her sweet tyrant just the way he is.

A group of young girls are cornered on the roof of their school when everyone else has turned into zombies. Realizing that the chances of being rescued are slim, they begin planning their escape using their knowledge and skills. In the girls' desperate struggle to survive, they must also find time to contemplate their friendship.

Two years ago, Junichi Tachibana had a date on Christmas Eve but was stood up instead. Since then, he has had a hard time showing others his true feelings in fear of being rejected again. However, as luck would have it, Junichi may have a second chance at love when he meets several girls whom he becomes romantically interested in: Haruka Morishima, the energetic and popular upperclassman with a love for cute things; Kaoru Tanamachi, his childhood friend who harbors secret feelings for him; Sae Nakata, the timid transfer student who is shy around men; Ai Nanasaki, a girl on the swim team who has a bad first impression of Junichi; Rihoko Sakurai, a childhood friend with a love for sweets; and Tsukasa Ayatsuji, a seemingly perfect class representative who has a hidden dark side. As Christmas Eve approaches, Junichi can only hope that this will be the year he will finally spend the holidays with the one he truly loves.