The trio want to enjoy their summer break, but first they have to pass their exams, and it turns out poor Nagisa is an extremely poor student. Saki wonders if Shino could be convinced to help her study, even though she disapproves of their relationship.

Shino moves in with the trio, intended to begin work on breaking them up. Saki tells everyone stories about how they met in middle school., which involved Saki making Shino play video games. It turns out Naoya also has a story about how he met Shino...

The gang is heading out to the fireworks festival. After a failed experiment (which was not Nagisa's fault), Shino decides that Saki and Naoya need to have their first kiss with the fireworks display helping to set the mood.

Everyone's at the fireworks festival, but Naoya and Saki have been separated, foiling Shino's plans. Instead, Naoya has ended up watching the fireworks with Nagisa despite their plans to the contrary.

Rika kidnaps Naoya after drugging the others, hoping to seduce Naoya while the others are away. Naoya firmly rejects her advances, but this only inspires Rika to keep trying harder. Naoya then realizes escape is the only way out.

Rika moves in with Naoya and the others, and insists that sleeping in the same room with him in a non-sexual fashion should be completely permissible. Naoya agrees, but only if all the girls get to take turns sleeping in his room in a non-sexual fashion.

Saki really wants to go to the beach, but conversation about the trip is interrupted by Mirika drying her bra out where Naoya can see it. One thing leads to another, and the girls are soon competing to see whose bra excites Naoya the most.

Naoya and the girls depart for Okinawa. The trip gets off to a bumpy starts when their plane encounters turbulence, and Naoya panics. Once they get to their vacation home in Okinawa, the girls put on their swimsuits.

Mirika has kidnapped Naoya and locked him in a room while Saki and the others try to find the key. Shino is taken aback by Mirika's resolve, and begins to question the way she's been hiding her own feelings.

Shino and Naoya are stranded on an uninhabited island, and Shino has ended up naked again. Has the time finally come for Shino to confess her feelings? Meanwhile, Saki and the others have realized that Naoya and Shino are missing.