High school teacher Yakuro Kuji, twenty-six, is dumped by his girlfriend because he lacks masculinity. Pale-skinned and slender, he has always struggled with a feminine appearance and feels deeply insecure. Distraught, he is cornered by a group of unpopular male students who ask him to advise a club for “love-loser boys.” While hesitating, he is interrupted by Akano, the brilliant and beautiful president of the Biology Club—also a model, influencer, and top academic performer. She bluntly explains that male attractiveness is rooted in biology, using the example of a peacock’s extravagant tail feathers to argue that showy traits exist precisely because females prefer them, and that men who fail to signal dominance are evolutionarily disadvantaged.

Akano then pressures Yakuro to become the Biology Club’s advisor. It soon becomes clear that she has a secret motive: she has harbored a crush on him since childhood. Eight years earlier, when both were young, Yakuro unknowingly intervened in a fight involving Akano and her older sister, mistaking the tomboyish Akano for a boy. That encounter inspired Akano to become a “good woman” and pursue him.

The story follows Yakuro and Akano as they tackle various problems at school. Akano applies biological concepts—such as adelie penguin rivalries, the disadvantages of promiscuous “bitch” behavior, peacock mating displays, reciprocal altruism, and the Red Queen hypothesis—to resolve conflicts among students and staff. Her brutally logical, often coldblooded explanations shock everyone but prove strangely effective. Yakuro’s own romantic situation remains complicated: he is a responsible teacher who resists crossing the line with a student, even as Akano grows more determined.

Later arcs delve into Akano’s family past. Her mother had an affair, and Akano was born out of wedlock—a fact that torments her. The revelation that she is, biologically speaking, a “cuckoo” child (an offspring raised by an unwitting parent) forces her to confront her feelings about family and identity. A school trip to Kyoto leads to a major confrontation between Yakuro and Akano, culminating in a feverish, emotionally charged episode.

The supporting cast includes troubled students such as the rebellious Mitsuki Rami, classmates Terii and Ginbe who feud over a boy, the delinquent Takagaki who challenges his group leader, and a female teacher Nanbu who complains about her boyfriend. Each problem is reframed through the lens of evolutionary biology, producing both comedy and harsh truths. Yakuro, the straight-laced adult, frequently finds himself pulled into chaotic situations, but his sincerity and willingness to act when it counts earn him respect.

Through these episodes, the series balances romantic comedy with pointed biological observations about human mating strategies, social hierarchy, and the raw imperatives of reproduction. Akano’s obsessive pursuit of Yakuro—despite her usual composure—drives the central romance, while the biology lessons keep the narrative unpredictable and intellectually playful.