Love has never really been a concern for Mitsuyoshi Tada, and as the aspiring photographer enters his second year of high school, it truthfully couldn't be further from his mind. However, things just might change after he meets a bright and bubbly foreigner named Teresa Wagner while he was taking pictures of a cherry blossom tree. Nevertheless, after she asks him to photograph her, the two soon separate... only to meet each other again twice more that same day! Finding Teresa just as she is caught in a sudden downpour, Tada invites her to his family's coffee shop to dry off. There, she explains that she was separated from her traveling companion, a no-nonsense redhead named Alexandra ''Alec'' Magritte. When Alec reunites with Teresa shortly after, they say their goodbyes, expecting to part ways for good—but the two unexpectedly show up as transfer students in his class the next day. Teresa and Alec quickly get used to their lives at Koinohoshi High School and decide to join Tada in the photography club, along with his narcissistic friend Kaoru Ijuuin, the idol-obsessed Hajime Sugimoto, serious class rep Hinako Hasegawa, and the dog-like Kentarou Yamashita. With these two peculiar additions to his equally eccentric group of friends, Tada's second year of high school is about to get even livelier, and he might need to start rethinking his approach to love. [Written by MAL Rewrite]

Iwaki Tomonori is an average 15-year-old boy who likes older women. He happens to have a crush on his teacher, but soon thereafter, learns she has become engaged. He heads home brokenhearted, only to find a 12-year-old girl named Rizel at his home, who he learns the Japanese government has married him to against his will. Furthermore, he learns Rizel is no ordinary girl; she is a biochemically engineered human, and her creators (her "papa"s, as they are often referred to) promise to waive multiple bills of Iwaki's parents in exchange to be allowed to stay at their house, and thus Iwaki's life with Rizel begins.

The once peaceful city-state of Lisvalletta has found itself beset by a dangerous new drug called Anthem. The side effects of the drug allow the user to enter a state of Overdrive, wherein they mutate into superpowered beasts with inhuman abilities. With the police powerless to stop this new threat, the responsibility falls upon the Special Crime Investigation Unit SEVEN-O. To offset the dangers of this work, the investigators work under the patented "Double Decker" system, which requires them to team up in "buddy cop" pairs. As a child, average police officer Kirill Vrubel fantasized about being a hero who would save his school from a random terrorist attack. His chance to be a hero arrives when his landlady blackmails him into searching for her lost cat. Upon arriving and falling asleep in an abandoned warehouse, Kirill finds himself in the middle of a hostage situation involving an Anthem user. By teaming up with SEVEN-O detective Douglas "Doug" Bilingam, Kirill earns his spot as the newest member of SEVEN-O. Now, with the help of this secret organization, he may finally achieve his dream of becoming a hero. [Written by MAL Rewrite]

Subaru Mikazuki is a 23-year-old mystery novel author, major introvert, and an awkwardly shy person. He would much rather stay home to read a book than go outside and interact with others. Further exacerbating this life of solitude, his parents tragically died in an accident many years ago, leaving him alone in the world. One day, while giving offerings at his parents' grave, Subaru runs into a small grey and white cat named Haru, which he ends up taking home with him. Subaru, however, has never taken care of anyone else in his life—can he even take care of a cat? Haru is grateful toward Subaru, as he gives her all the food she wants—a luxury for a cat who is used to a rough life on the streets. But she notices that Subaru can't even seem to take care of himself! Will she be okay with this dunce? Doukyonin wa Hiza, Tokidoki, Atama no Ue. tells the story of an unlikely friendship between a human and a cat who try to foster an understanding with each other. [Written by MAL Rewrite]