Iori spends her holidays working as an actress, shooting a movie at the waterside of a lake, which has a mysterious small island called Lover's Island at its center. Ichitaka, on a biking trip, coincidentally makes a stop at the location where Iori is shooting. Meanwhile, Itsuki returned from her job as a molding artist in the United States and plans to meet her childhood friend Yosuke to fulfill a promise they made ten years ago. Walking along the railroad track she, Yosuke and Ichitaka went along ten years ago, Itsuki is confused when she sees the lake with the small island in it at one side of the track, as she does not remember there being a lake. Yosuke, along with three of his biker friends, is also on his way to meet with Itsuki. However, the other bikers reveal to him that they are planning to rape Itsuki. He drives ahead to save Itsuki from them, but drops from his motorbike just as he crosses her path. The other bikers close in on him, stab him and let him drop into the lake (which he can not remember being there when he was a child). As the bikers spot Itsuki, she runs away.
Yasumasa and his friends want to pick up Iori at the Lake Side Hotel, but she already left as her shooting finished early. Meanwhile, she meets Ichitaka and they decide to take a boat and row across the lake to the island. As they arrive, Ichitaka recognizes the island as the place he, Yosuke and Itsuki visited as children, although back then there was no lake around it. Just then, Iori and Ichiitaka hear Itsuki on the other side of the lake screaming for help as the bikers found her and now want to rape and kill her. Ichitaka quickly rows over, leaving Iori alone on the island. He manages to hold back two of the bikers, but their leader knocks Itsuki out and abducts her on his motorbike. As it starts to rain heavy, Ichitaka follows them, while Yasumasa and his friends, who suddenly show up, take out the two bikers. Ichitaka takes a shortcut across a fragile old plank bridge to cat
Iori pasa sus vacaciones trabajando como actriz, filmando una película en la orilla de un lago, que tiene una pequeña isla misteriosa llamada Lover's Island en su centro. Ichitaka, en un viaje en bicicleta, casualmente hace una parada en el lugar donde Iori está filmando. Mientras tanto, Itsuki regresó de su trabajo como modeladora en los Estados Unidos y planea conocer a su amigo de la infancia Yosuke para cumplir una promesa que le hicieron hace diez años.
湖上も“浮かぶ恋を成就する島”に向けて伊織を乗せたボートを漕ぐ一貴。見覚えのある風景に蘇る幼馴染み、いつきとの10年前の約束…。
「いっチャン！」
遥か遠くの湖岸で不良たちに追われ、助けを求めるいつきの姿が一貴と伊織の目に飛び込んできた！ 運命に導かれるように引き寄せられる３人の、ひと夏に起こったもう１つの「I"s（アイズ）」の物語です。
