Kenta, a frustrated young man desperate for romance, is visited by Suwatee, the Benzaiten Goddess, who grants his wish to be with beautiful women. By summoning fragments of the Seven Great Northern Stars to Earth, Suwatee brings seven women into Kenta's life, but with a catch: he must sleep with each of them or they will forget he ever existed. After rescuing the gentle Kaori and the rebellious Misao from dangerous thugs, Kenta begins his journey to fulfill the goddess's provocative condition.
Kenta meets Chisato, a passionate otaku and aspiring manga artist, and helps her connect with a professional publisher. After Chisato performs as the hero "Space Detective X-2" in a local show, she and Kenta share an intimate encounter that results in a brief hospital stay, where Kenta meets a mysterious new girl named Haruna.
When nurse Haruna disappears, Kenta discovers she has been kidnapped by the vengeful spirit of Kyoko, a woman betrayed by Mr. Okamura fifty years prior. By traveling back in time to resolve this tragic grudge, Kenta not only saves Haruna but also uncovers a secret, romantic history involving Suwatee and Shuree, leading to a spirited love triangle in the present.
Kenta takes a part-time job at a struggling resort hotel alongside Suwatee and Shuree, who have been temporarily turned into humans as punishment. While attempting to make a quick profit on the beach, Kenta rescues Mahoko, the rebellious granddaughter of a rival hotel owner, from a group of thugs. Now smitten, Mahoko joins the crew, further complicating the romantic tension between Kenta and the two goddesses.
During a local summer festival, Shuree attempts to spark romance between Kenta and Suwatee through a series of jealous ploys. However, the mood shifts when Mahoko's grandfather tries to force her into a strict academy to keep her away from Kenta. As Kenta and Mahoko share an intimate bond, the conflict between the young lovers and the controlling grandfather reaches a boiling point.
Mahoko's grandfather challenges Sanada to a surfing contest to decide if the group can remain on the beach. Sanada, haunted by the tragic death of his former lover, must overcome his deep-seated trauma to return to the water and protect his friends. As the competition ends in mutual respect, Shuree shares a bittersweet farewell with Kenta before departing for Okinawa, leaving Kenta and Suwatee to finally confess their love for one another as the summer season comes to a close.