The story takes place in a small town located in Gunma Prefecture and follows Takao Kasuga, a middle school bookworm whose favorite book is Charles Baudelaire's Les Fleurs du mal, after which the series is named. One day after school, he discovers and impulsively steals the gym clothes of Nanako Saeki, the classmate he has a crush on. However, a lonely girl named Sawa Nakamura happens to catch him in the act. Nakamura blackmails Kasuga into a "contract," under the threat of revealing his secret.
A middle school student who has a huge love for literature and a crush on Saeki. Upon seeing her gym clothes while alone in the classroom, Kasuga is unable to resist and begins smelling them, but then panics after hearing something and impulsively steals the girl's clothes. He soon discovers that his sinful act was witnessed by Sawa Nakamura, an isolated loner in his class who blackmails him into forming a contract, tying them as "friends". He many times has to bear the shame of her demands, but also acting on his own, begins to date Saeki. While initially disliking her requests and their meetings, Kasuga soon feels attracted to her personality, and realizes that Nakamura is actually lonely, longing to escape from the people of the town, much like himself. He develops strong feelings for her, promising to one day take her to the "other side". However, this causes him to break up with Saeki and hurt her feelings, which in turn brings a series of events led by Nakamura's and Kasuga's schemes that increasingly cause havoc to their school, and soon enough, the whole town.
Three years after the summer festival incident, Kasuga has moved to Ōmiya to restart his life. However, his family is now broken because of his past actions, himself becoming distant to his parents and society, and even losing the will to engage in reading literature. While having a few friends, he is quite reserved to the point of becoming awkward.
A classmate of Kasuga who sits behind him in their classroom. She is considered by others to be a strange, lonely and isolated girl, and has no friends. She shows no reaction to other people, and while remaining calm, she tends to talk back to others, calling people shit eaters. She is the sole witness to Kasuga's breakdown upon facing Saeki's gym clothes and, having knowledge of this fact, she blackmails him into becoming his "friend" if he doesn't want to let the school know his crime. She repeatedly calls Kasuga a "sick minded" person, vows to "peel off all of his skin" and forces him into shameful and torturous situations, displaying a sadistic personality. Nakamura has emotional outbursts when expressing herself to Kasuga, the only one aware of this weak side of hers, which leads him to deduce that her quaint behaviour is actually a demonstration of her desire to "escape" with him, ceasing to be alone and taking both "to the other side" of the mountains. Due to this, Kasuga learns to understand and earn Nakamura's admiration, and the two begin plotting together. However, Nakamura earnestly believes that even if Kasuga chooses to stay with her, she will ultimately be isolated.
Another girl from Kasuga's class, on whom he has a crush, Saeki is deemed to be the top student of their class, and is considered to be a popular and beautiful girl. After he defends Nakamura from the rest of their class and supports him, Saeki begins to take an interest in Kasuga, especially his passion for Les Fleurs du mal and how he is able to show his true self, without having to hide his personality; desires or interests. The two start dating and Saeki reveals how she longs for a life in which she doesn't have to fake herself with being well-mannered, composed and focused on study. She later lives in Utsunomiya, has gotten a new boyfriend who, according to Tokiwa, "looks a lot" like Kasuga.
A character first introduced in the second part of the story, she is portrayed as a tall, red-haired beauty of Kasuga's year, revered by his friends, but known to date an older guy from another school. Kasuga notices her holding a copy of Les Fleurs du mal in a bookstore and discovers her passion for books. She helps him regain his interest in literature once more, and becomes close to him, to the point of inciting her boyfriend Koji's suspicion towards Kasuga.
Saeki's best friend. Outspoken and hotheaded, she cares deeply for Saeki and begins to resent Kasuga for the pain he's caused her. She later gets the truth from Saeki when she realises her friend has been spying on Kasuga and Nakamura. She feels the urgency to tell the police the deeds of the couple, only to be scolded by Saeki, who believes she'll be able to pull Kasuga out of his mess. As events develops and she realises Saeki's corruption as well, she is unable to hold out and becomes responsible for exposing Kasuga and Nakamura, but in the process also affects her best friend.
The manga was launched in the first issue of the Japanese manga magazine Bessatsu Shōnen Magazine published by Kodansha in September 9, 2009 and ended on May 9, 2014.Kodansha has compiled the 57 chapters into 11 volumes from March 17, 2010 to June 9, 2014. The series was licensed in North America by Vertical in September 2011, with the first volume published on May 8, 2012 and the last volume on October 14, 2014.
Forgetting his copy of Les Fleurs du mal at school, Kasuga goes back and stumbles upon Saeki's gym uniform, stealing it in a panic. Nakamura tells him that she saw him stealing the uniform and forces him to form a contract with her. When he doesn't write her an essay, she strips him and forces him to wear the uniform. After Kasuga defends Nakamura from an accusation of stealing, Saeki tells him that he was really cool. Later, he manages to ask her out on a date. Nakamura meets him before the date and makes him wear the uniform underneath his clothes.
Kasuga takes Saeki to a used bookstore and gifts her a copy of Les Fleurs du mal. In a park, Saeki asks him to enter into a relationship with her. Nakamura splashes him with a bucket of water, revealing the uniform underneath his clothes, and Kasuga flees. Saeki mishears Nakamura teasing Kasuga about her and thinks that she wants to have sex with Kasuga. After failing to tell Saeki about his theft, Kasuga begs Nakamura to tell her the truth. Nakamura and Kasuga meet in the school at night and proceed to heavily vandalize it. Kasuga writes a confession on the board, draws the flower from the cover of Les Fleurs du mal on the floor, and places the uniform in the center.
The next day an assembly is called and students are sent home, but Kasuga isn't incriminated because his name in the confession was covered by ink. Saeki confronts Kasuga, recognizing the flower drawn on the floor and he requests a breakup. She refuses and visits his home later, requesting that Kasuga be more open to her. Kasuga's mother discovers the ink-stained clothes from the previous night and Kasuga runs away. He meets Nakamura and she tells him to ride his bicycle towards the mountains. Saeki finds them at night, and tries to make Kasuga come back. However, Kasuga is unable to choose between the two girls, estranging both of them. The police come searching for Saeki and drive them all to the police station.
A month after their encounter in the mountains, Saeki breaks up with Kasuga. Resolving to help Nakamura, Kasuga writes an essay for her. However, she runs away from him and Kasuga ends up meeting her father at their house. Kasuga goes into her room and finds her diary, which chronicles her boredom and attempted escape from tedium with Kasuga. Kasuga builds a makeshift hideout for them and decorates it with panties stolen from all the girls in his class, gaining Nakamura's approval.
Before the start of summer vacation, Kasuga places a pair of panties on top of a school statue. Saeki and Kinoshita follow him to his hideout and Saeki vows to punish them. Kasuga and Nakamura nail the panties onto plywood, planning to show them at the summer festival. Saeki discovers the plywood and lures Kasuga to his hideout. There, she rapes him, but Kasuga resists, causing her to burn the hideout down. Saeki confronts Nakamura, but she only hugs her, causing Saeki to admit that she's jealous of her. Meanwhile, a firefighter discovers Nakamura's planner at the scene of the fire.
30. "Softly Respiring in the Depths of Stifling Darkness"
31. "Sullied, Pure Gaze"
32. "I Will Love You!"
Police detectives visit Kasuga at his home and question him about the fire and the planner, but he denies involvement. His parents confront him about his activities and force him to stay home. Saeki visits him and tells him to turn himself in and stay in the town with her, but Kasuga rejects her advances. Saeki turns herself in to the police for the fire. Kinoshita tells the school about Kasuga's crimes. The school doesn't involve the police and tries to get him to admit that he was influenced by Nakamura. Kasuga's parents announce that they'll be moving over the vacation. The night before the festival, Nakamura breaks into Kasuga's house, attacking his father, and the two escape. Nakamura attacks Kasuga and asks him to kill her, but he refuses. The next day, the two purchase disguises, a kitchen knife, kerosene, and a lighter. Meanwhile, Kasuga's mother, Nakamura's father, and Kinoshita search for them at the festival. Kasuga and Nakamura climb to the top of a float while wielding a knife.
Kasuga and Nakamura pour kerosene on themselves and say their final words, cursing the town and themselves. Just before they immolate themselves, Nakamura pushes Kasuga over the railings of the float, but she is tackled by her father before she can burn herself. A few years later, Kasuga is going to high school in a new city and he finds that he still can't forget Nakamura. Kasuga finds Tokiwa looking at Les Fleurs du mal in a used bookstore and she offers to lend him a novel. The novel rekindles his love of books and she starts lending him novels frequently. One day she forgets to bring the novels so Kasuga goes with her to her house. He discovers that she is currently working on a novel. Before he can look at it, Koji, Tokiwa's boyfriend, shows up outside her house.
Koji is initially suspicious of Kasuga but relaxes after seeing how timid he is. He invites him to come along with Tokiwa and him to their friends' hideout. Angry that Kasuga was the first guy that Tokiwa let into her room, Koji presses Kasuga on who he used to like, causing an argument between the Koji and Tokiwa. Tokiwa admits to Kasuga that she feels empty and Kasuga sees a resemblance to Nakamura in her. Later, Kasuga reads her manuscript, and is bought to tears because he can identify with the protagonist. He encourages her to write the novel. On their way home, Kasuga runs into Saeki, and the two meet up for lunch the next day. Saeki questions Kasuga on why he isn't searching for Nakamura anymore and accuses him of using Tokiwa as a stand-in for her.
Koji and Tokiwa make up and he apologizes to Kasuga. Saeki's words come back to Kasuga and cause him to doubt his relationship with Tokiwa, but he reminds himself that Nakamura is elsewhere now. Emboldened, he visits Tokiwa at her workplace and asks her to go out with him, saying that he will be the one to save her. She breaks up with Koji and accepts. After they go out for a while, Tokiwa proposes that they visit Kasuga's hometown, but Kasuga refuses. Kasuga's father receives a phone call that Kasuga's grandfather collapsed and is going to die soon. Kasuga decides to go back with him to their hometown.
Kasuga helps keep his grandfather company while he turns cold, but he misses his death. Kasuga's relatives blame him for their grandfather's death. Kasuga sees Kinoshita at the funeral and the two meet at a diner at night. Kinoshita tells him that she regrets being left behind by Saeki and being stuck in her town. Before she leaves, she gives Kasuga a note saying where Nakamura moved to. Tokiwa finishes her novel and asks Kasuga to read it, but he refuses and tells her about his past. Kasuga tells her that he wants to visit Nakamura so that he can put her in the past and be with Tokiwa. Tokiwa says that she'll go with him. The couple takes the train to Tokawa Station in Chōshi, Chiba and finds the eatery which Nakamura's mother owns. They order a meal and Kasuga and Nakamura greet each other.
53. "To Know Whether the Sea Is Truly Generous and Kind"
54. "In The Golden Sunset"
55. "Following Time's Passage"
56. "We Are Those Who Wish"
Final Chapter. "The Stuff of Our Souls"
At a nearby beach, Kasuga asks Nakamura her why she shoved him off the float back then and Nakamura says she forgot. Kasuga roughhouses Nakamura and tells her that he's happy she didn't disappear. She punches him and the three play with each other. Later, Kasuga is now in college and re-reads Les Fleurs du mal, enjoying it. Tokiwa and him are still dating and she is working on another novel. Kasuga dreams about his future with her and about his friends reuniting with estranged loved ones. When he wakes up, Kasuga starts writing in his empty book. The final chapter shows the story from Nakamura's point of view with people depicted as scary black blobs and darkness threatening to seep into her until she meets Kasuga.
The anime adaptation is directed by Hiroshi Nagahama and produced by Zexcs. It aired in Japan between April 5 and June 29, 2013 and has been licensed by Sentai Filmworks in North America. Crunchyroll has the streaming rights in Australia, North America, UK and other territories. The anime itself was animated using rotoscoping techniques, causing some online controversy among fans of the manga at the time of its original release. The opening theme is "Aku no Hana" (惡の華?) by Uchūjin with guest vocalists Noko, Mariko Gotō and Shiho Nanba, while the ending theme is "〜花〜 A Last Flower" by Asa-Chang & Junray.
Kasuga is a literary nerd who goes to middle school in a small town. He idolizes Baudelaire and is in love with his beautiful and brilliant classmate Saeki. In his class there is also a redheaded outcast called Nakamura. One day after class, he returns to the classroom for a book he's forgotten, only to find Saeki's sports clothes on the floor.
"Flowers of Evil 2 of 13"
April 12, 2013
Kasuga steals Saeki's clothes. The next day his guilty conscience makes him uncomfortable in class. When riding his bike, he encounters Nakamura who tells him she saw him steal the clothes. The next day, she meets him in the library and blackmails him into following her orders. She pushes him into Saeki's breast and demands that he write an essay about the experience.
"Flowers of Evil 3 of 13"
April 19, 2013
Kasuga meets Nakamura after school in the library. He didn't write the essay Nakamura asked for. As a form of revenge, she undresses him and forces him to wear Saeki's clothes. The next day someone steals money in a locker. Nakamura gets accused. Because he was with her, Kasuga takes her defense. As a consequence, the class thinks he's in love with Nakamura.
"Flowers of Evil 4 of 13"
April 26, 2013
After school, Kasuga bumps into Saeki. She reveals that she thinks the way he defended Nakamura was pretty cool. Another day, Kasuga carries boxes for Saeki. He asks her on a date at the bookshop. Nakamura sees them and later forces Kasuga to wear Saeki's clothes underneath his own for the date.
"Flowers of Evil 5 of 13"
May 4, 2013
The date goes well. Nakamura, who's been following them, asks Kasuga to kiss Saeki. He refuses, asking Saeki to be in a platonic relationship. As she accepts, Nakamura dowses him in water, revealing the clothes underneath. He runs away before Saeki notices. Nakamura promises she'll stop interfering.
"Flowers of Evil 6 of 13"
May 11, 2013
The class learns of Saeki and Kasuga's relationship. Nakamura becomes friends with Saeki. In the library, Nakamura tells Kasuga that what Saeki really wants is to have sex with him. Saeki overhears her, and doesn't show up the next day. Kinoshita asks Kasuga to deliver handouts to Saeki. He goes and is taunted by Nakamura on the doorstep.
"Flowers of Evil 7 of 13"
May 18, 2013
Saeki thinks Kasuga might be with Nakamura, but when asked if hiding anything, Kasuga denies, and she decides to trust him. Kasuga then pleads Nakamura to tell Saeki the truth as he can't. Nakamura asks him to meet her in front of the school at midnight. She convinces him to write his deeds on their classroom chalkboard and then they proceed to extensively vandalize the room.
"Flowers of Evil 8 of 13"
May 25, 2013
Nakamura and Kasuga slowly walk home, hand in hand. The next day, the whole class is in uproar. The ink covered Kasuga's name. Saeki is devastated, her clothes at the center of the destruction. The whole school gets informed. Kasuga pukes. Saeki confronts him. He breaks up with her. She notices the drawing on the floor was the same as on his favorite book.
"Flowers of Evil 9 of 13"
June 1st, 2013
Saeki refuses to break up. The next day, Kasuga is absent. Saeki asks Nakamura what her relationship with Kasuga is. She says she's contracted to reveal his deviance. Saeki argues he's not a deviant. She goes to Kasuga's and make a case for him through the window. His mom finds his stained clothes and he runs away. Saeki sees his mom looking for him.
"Flowers of Evil 10 of 13"
June 8, 2013
Kasuga goes up the mountains with Nakamura on his bike. They stop because of the rain. Saeki goes looking for Kasuga and finds them. Nakamura undresses him again. When asked to choose between the two of them, he stands his middle ground and upsets both. A police car shows up because of Saeki's parents and brings them all home.
"Flowers of Evil 11 of 13"
June 15, 2013
One month later, summer. The three have been ignoring each other. On Kinoshita's initiative, Saeki and Kasuga talk, only to break up. Kasuga is a shell of his former self. His mother is upset. He pukes. He knows Saeki is going to be alright without him, but even in his dreams, he can't stop thinking about Nakamura.
"Flowers of Evil 12 of 13"
June 22, 2013
Kasuga writes an essay to Nakamura. Kinoshita asks Kasuga's friends what is wrong with him. Kasuga tries to give his essay to Nakamura, but she ignores him, so he starts reading it to her. She runs away. He goes to Nakamura's to deliver the essay. On the doorstep, he is invited in by the father who says he's her first friend.
"Flowers of Evil 13 of 13"
June 29, 2013
Kasuga enters into Nakamura's room. He finds her diary and starts reading it. He recalls what happened. Nakamura comes back, seizes the diary and runs away. He follows her and this time catches up to her. This time, he asks her to make a contract with him: they'll do what they can in order to leave for good someday.