On his first day of junior high, Kei Enjoji fell in love at first sight. His heart was immediately captured by the gorgeous Ranmaru Samejima, a young kendo prodigy, and the two slowly formed a deep romantic bond. Now adults and living happily together as a couple, things seem to be going well for Ranmaru and Kei. One morning, host Kei arrives home after a night out drinking with a client. A frequent occurrence, Ranmaru is initially unfazed by Kei's drunken state—until he notices three extremely suspicious things: Kei's clothing smells of makeup, his chest is stained with lipstick, and he is carrying matches branded with the name of a love hotel. To top it all off, a woman calls the apartment asking for "Kei-chan," and at that, Ranmaru loses it. Hurt by Kei's unfaithful actions, Ranmaru storms off. He spends the day reminiscing about years of precious memories, deciding to put them behind him for good—and when he is "picked up" by a woman on the streets, he comes to terms with reality. If this is what society wants, and if Kei has truly fallen for a woman, then who is he to stand in their way?

In the distant future, on a dying Earth, human beings are synthetically produced and raised by artificial intelligence to hold specific roles in society. Among them lives Godo Shingo, a candid young cadet who demonstrates uncommon kindness toward living creatures and robots alike. Although Godo's superiors ridicule him for showing attachment to his nursemaid robot, Olga, he makes quite an impression as a sharpshooter and is entrusted with a special task—to capture the legendary immortal bird Phoenix, which has destroyed countless spaceships. However, his life changes dramatically after falling in love with Rena, the president's daughter who is also the fiancée of Rock Holmes—the Chief of the Science Department. After the pair fails to elope, they are separated, and Godo is sentenced to prison camp labor. Luckily for him, their companions Olga and Pincho—Rena's alien pet—escape unnoticed and come to his rescue. Hi no Tori 2772: Ai no CosmoZone follows an engaging adventure in outer space, exploring the idea of selfless love as an unparalleled power.

Demonic Vice-Commander of the Shinsengumi, Toushirou Hijikata, acquires a cursed sword—one which completely rewrites his personality, morphing him from a hard-boiled, no-nonsense cop into a hopeless otaku. As he struggles to break the curse, an ambitious new member of the police force, Itou Kamotarou, seizes the opportunity to depose Hijikata in his bid for power within the organization. However, Itou's scheme is revealed to be more devious than anyone imagined, and the very existence of the Shinsengumi is thrown into peril. In another time and place, the Yorozuya squad is suddenly greeted by a potential new recruit. Before them is a mysterious young woman named Pirako Doromizu who hides a penchant for extreme violence behind her smiling, enthusiastic exterior. However, unbeknownst to Gintoki and the others, Pirako has strong ties to one of the ruling figures of the Kabuki district of Edo, and her arrival sets off a chain reaction that throws the inhabitants of the district into a civil war.

Taking place after the events of Heaven and Earth and before Exodius, Behind the Line depicts the moments of boys and girls after Soushi Minashiro returned home.