Opening scene shows two woman diving in the ocean. It then cuts to Iori Kitahara, who has just arrived in Izu, getting picked up by his uncle. They drive back to his uncle's diving shop, Grand Blue, where Iori will be staying while he attends university. Iori notices a woman emerging from the sea before turning to enter the shop. Upon opening the door to Grand Blue, Iori is greeted by the sight of a group of naked, drunk, and heavily muscled men playing Yakyuken. In shock he runs out of the shop, only to see two men from the group chasing after him. They eventually manage in catching him and dragging him back to the shop. They then explained to Iori on the circumstances of what he had seen earlier, to pick who would be on equipment duty.
Iori decides to join Kotobuki, one of the men that chased him, on equipment duty. While he is in the middle of it, a beautiful young woman greets Iori, much to his confusion. Seeing that Iori is unable to recognise her, she reminds him that she is his older cousin. After they return to the shop, Kotobuki and Tokita admonish Iori for complaining and then coerce him into drinking and playing Yakyuken. Chisa returns to the shop as Iori gets swept up in the antics of the club, getting drunk and stripped of all clothing except his boxers. Disgusted with his current state, she quickly distance herself from Iori. Despite being distraught over his treatment by Chisa and concerned about his orientation, Iori is again forced into another drinking party.
The next day, Iori awakens to find himself passed out nearly naked in front of the lecture hall, just in time for his orientation. After a brief encounter with a student, Iori, who is down to his boxer, attempts to convince Chisa to share some of her clothes with him, so he can get dressed, but he sounds like a pervert and is chased around campus by a campus security guard. While he hides, Iori was found by the curious Kōhei, who punches him and quickly alerts the authority after Iori asked for his clothes. On the run again, Iori fortunately bumps into Nanaka and Kotobuki, who are recruiting members for the Peek a Boo diving club on the campus ground. Seeing Iori's desperation, Kotobuki agrees to give him some clothes if Iori can recruit another member to the club. Iori immediately proceeds to find and tricks Kōhei into joining the club with him.
Eventually, Iori, along with Chisa and Kōhei, is initiated into the "Peek a Boo" Diving Club by Tokita and Kotobuki. As part of their initiation, Iori and Kōhei are pressed into a drinking contest where even the "water" is a large glass of vodka.
Characters in Order of AppearanceEdit
- Chisa Kotegawa
- Nanaka Kotegawa
- Iori Kitahara
- Toshio Kotegawa
- Shinji Tokita
- Ryuujirou Kotobuki
- Kouhei Imamura
Difference(s) from the MangaEdit
- In the opening scene, Nanaka is seen diving with Chisa, unlike in the manga where she is diving alone.
- During the beach scene, Iori spots Chisa in the distance instead of Nanaka.
- There's no flashback scene of Iori and Chisa's childhood days in the manga.