Kazuya Kinoshita is a 20-year-old college student who has a wonderful girlfriend: the bright and sunny Mami Nanami. But suddenly, he doesn't. Without warning, Mami breaks up with him, leaving him utterly heartbroken and lonely. Seeking to soothe the pain, he hires a rental girlfriend through an online app. His partner is Chizuru Mizuhara, who through her unparalleled beauty and cute demeanor, manages to gain Kazuya's affection. But after reading similar experiences other customers had had with Chizuru, Kazuya believes her warm smile and caring personality were all just an act to toy with his heart, and he rates her poorly. Aggravated, Chizuru lambastes him for his shameless hypocrisy, revealing her true pert and hot-tempered self. This one-sided exchange is cut short, however, when Kazuya finds out that his grandmother has collapsed. They dash toward the hospital and find Kazuya's grandmother already in good condition. Baffled by Chizuru's presence, she asks who this girl might be. On impulse, Kazuya promptly declares that they are lovers, forcing Chizuru to play the part. But with Kazuya still hung up on his previous relationship with Mami, how long can this difficult client and reluctant rental girlfriend keep up their act?

On a rainy morning in Tokyo, Takao Akizuki, an aspiring shoemaker, decides to skip class to sketch designs in a beautiful garden. This is where he meets Yukari Yukino, a beautiful yet mysterious woman, for the very first time. Offering to make her new shoes, Takao continues to meet with Yukari throughout the rainy season, and without even realizing it, the two are able to alleviate the worries hidden in their hearts just by being with each other. However, their personal struggles have not disappeared completely, and as the end of the rainy season approaches, their relationship will be put to the test.

Koyomi Araragi has recently survived a vampire attack and met several girls plagued by supernatural entities. On top of all this, he wakes up one morning to find himself kidnapped and tied up by his girlfriend Hitagi Senjougahara. Araragi's sister Karen has run afoul of Deishuu Kaiki, a swindler who once conned Senjougahara's family. As a result, Senjougahara has imprisoned Araragi to keep him safe from the devious Kaiki. But when Araragi receives a frantic message from Karen, he sets out to rescue her. Along with Karen's troubles, Tsukihi, Araragi's other server, faces issues of her own. And when two mysterious women step into their lives, not even Araragi can anticipate their true goals, nor the catastrophic truths about his family soon to be revealed.

One year ago, Sagiri Izumi became step-siblings with Masamune Izumi. But the sudden death of their parents tears their new family apart, resulting in Sagiri becoming a shut-in which cut her off from her brother and society. While caring for what's left of his family, Masamune earns a living as a published light novel author with one small problem: he's never actually met his acclaimed illustrator, Eromanga-sensei, infamous for drawing the most lewd erotica. Through an embarrassing chain of events, he learns that his very own little sister was his partner the whole time! As new characters and challenges appear, Masamune and Sagiri must now face the light novel industry together. Eromanga-Sensei follows the development of their relationship and their struggle to become successful; and as Sagiri slowly grows out of her shell, just how long will she be able to hide her true persona from the rest of the world?