New high school transfer student Makoto Hitsujiya encounters the socially reclusive Takehiro Kokudou and soon discovers that Kokudou possesses a mysterious notebook detailing Bugs. These are not computer errors but inexplicable glitches in reality itself, phenomena that occur only when a precise sequence of actions is performed in the physical world. Ranging from the comically trivial to the physically impossible, a specific button combination on a vending machine might cause bird droppings to fall on a precise spot, while other sequences can grant feats of superhuman strength. Fascinated by these anomalies that defy the laws of science, Hitsujiya becomes drawn into Kokudous world, and the two begin experimenting with and documenting these strange exploits.

The narrative takes a sharp turn when Hitsujiya, driven by academic insecurity, decides to use a Bug rumored to rewind time to ace an exam. The ritual requires performing a bizarre, embarrassing dance naked in the schoolyard during a solar eclipse. The attempt fails catastrophically. Instead of traveling back, Hitsujiya is subjected to public shame and social ruin, his life spiraling over the next forty years until he becomes a homeless outcast. It is only in this future, after a tense reunion with Kokudou, that he learns the truth. The Bug does work, but its window is minuscule, resetting time by mere minutes. After another attempt, Hitsujiya finally returns to his high school moments before his original mistake, forever changed by the horrifying glimpse of a wasted future he now has the chance to avoid.

The story is set in a contemporary Japanese high school and its surrounding town, a seemingly ordinary world where the extraordinary is hidden just beneath the surface. Hitsujiya is a charismatic but flawed everyman whose kind nature is often at war with his ego and curiosity, while Kokudou is a lonely genius whose encyclopedic knowledge of the Bugs is matched only by his desperate desire for a true friend. They are later joined by Hashira Yuki, a brilliant but joyless classmate who sees the Bugs as a potential escape from her soul-crushing academic pressures.

The series unfolds through several notable arcs. The initial discovery phase establishes the rules of the Bugs in a series of lighthearted, experimental vignettes. This gives way to the life-altering consequences of the Eclipse Ritual, which redefines the stakes from mere amusement to survival and regret. Subsequent chapters delve into psychological horror, such as experiments with lucid dreaming Bugs that trap users in nightmarish mental constructs. As the trio explores more dangerous hacks, a girl with a stalker-like obsession over Hitsujiya joins the cast, shifting the narrative from episodic, horror-comedy explorations toward a more focused serialized story about the origins of the Bugs and the mysterious nature of Kokudous notebook, whose cover features a sticker that seems to evolve as they use it.