Sachio was camping with his fiancée, Kiko, in the lush mountains, enjoying uninhibited sex even in broad daylight. That blissful time was shattered when a bizarre-looking man and woman suddenly appeared. When Sachio regained consciousness, he found himself bound to a chair in an unfamiliar room. As he worried about Kiko's safety, Sachio heard sounds from the couple. Voices that could be described as neither pleasure nor pain...

A wedding invitation arrives at a certain udon shop. Upon seeing the sender's name, the shop owner, Kazuyoshi, vividly recalls scenes from his apprenticeship days as if they happened yesterday... In his youth, Kazuyoshi fell in love with the taste of udon and became an apprentice at a quaint seaside udon shop. He fell in love at first sight with the shop's proprietress, Hideko. However, Hideko harbors feelings for the taciturn chef, Shinsuke. To put an end to this complicated situation, Kazuyoshi challenges Shinsuke to an udon competition, with his marriage to Hideko on the line.

Fumiko and Chitose, the second and third sisters of three sisters, work as waitresses at a coffee shop. With her boyfriend's birthday approaching, Fumiko can't concentrate on her work, imagining that Tsutsuji, the eldest sister with bad habits with men, will seduce him. Suddenly, a man with a knife and a modified gun bursts into the shop.

Nymphomaniac teacher Noa provides a private "Sex Education" lesson to her delinquent student, Maho Sawai, in a cramped classroom. The session takes a twisted turn as Maho—who hides a secret about his own anatomy. . Under Noa's provocative guidance, the line between fantasy and reality blurs. The roleplay becomes so intense that the two lose themselves in the "Futanari" world, leading to a frantic, simultaneous climax where setting and script are forgotten in favor of pure, raw ecstasy.

Minoru and Rina are treasure hunters who have pledged their future to each other. However, Rina loses her loved one and decides to return to her homeland of Japan on her own. However, she is pursued by the notorious Loco Moco couple, who are in the same business. Upon hearing that Rina has acquired a new treasure, they plot to steal it from her.

Asaka, a 24-year-old office worker, is fed up with her boyfriend's forceful caresses before she heads to work in the morning. She feels no love in their one-sided sex and, disgusted, decides to distance herself from him. However, she can't easily forget him. A female friend invites the depressed Asaka on a trip. Their destination is a town promoting itself as a "healing place for broken hearts"…

n the fourth installment of the "Futanarism" series, director Hitoshi Nimura focuses on the contrast between high-volume pleasure and stunning physical attributes. Featuring a cast where five of the six performers boast large cup sizes and all six possess massive hidden members (ranging from 18cm to 23cm), the film pushes the boundaries of the fantasy genre. Highlights include Aki Mizuhara’s self-stimulation, Alice Hoshi’s rhythmic performance, and Azusa Ayano’s unique fetish training. The feature culminates in a chaotic group encounter between Koyoi Yumesaki, Maho Sawai, and Kasumi, resulting in a total of 25 explosive climaxes that flow like a broken faucet.