Hikaru's life takes a shocking turn when the beautiful Student Council President, Tomomi-senpai, reveals her secret: she possesses a lactating body that requires sexual stimulation to find relief. Hired as her "baby" for a unique part-time job, Hikaru becomes entangled in an intense, boundary-pushing relationship with Tomomi, whose nurturing maternal side and insatiable desires lead them toward increasingly risky encounters throughout the school.
Hikaru continues to help Tomomi-senpai manage the effects of a supernatural lactation curse. During a trip to an amusement park with Hikaru's sister, Suzuka, Tomomi's breasts become painfully full, forcing the pair to find a secluded spot for a risky and urgent release.
Suzuka visits her brother Hikaru and discovers his secret sexual relationship with Tomomi-senpai, who suffers from non-pregnancy lactation. Driven by jealousy and her own hidden struggle with lactation, Suzuka reveals her secret, leading Hikaru to provide simultaneous relief to both women. Through an intense and lewd encounter, Hikaru helps them both release their breastmilk, cementing a strange, symbiotic bond between the three.
Hikaru balances his intense relationship with his lactating sister, Suzuka, and his growing feelings for Tomomi-senpai. After a romantic confession and an intimate encounter with Tomomi at the school pool, Hikaru reunites with Suzuka in Kyoto. The episode culminates in a daring encounter where Suzuka finds excitement in Hikaru's dual devotion to both her and Tomomi.