While walking on the sidewalk from Kamiyama High School after class, Tsukasa, who was followed by the other boys, Rui and their first-year juniors, Akito and Toya, he stops to see his phone having a notification.

“Huh??” Tsukasa said in confusion. “Oh~? What is it, Tsukasa-kun?” Rui asks curiously as he looks down at the screen of Tsukasa’s phone. “Hm? Tsukasa-senpai, what’s up?” Akito asks with his hands on his hips. “Tsukasa-senpai, what’s that?” Toya asked calmly.

Suddenly, the phone suddenly shines and brings them to a SEKAI that they haven’t been to before. This SEKAI was quite strange. The boys saw that the people in their own world had opposing genders of the ones in their original world and to their surprise, they saw four girls who were opposing genders of them!

The blonde haired girl, who had the same features and height as Tsukasa, was named Tsubasa Tenma, the purple haired girl, who had the same features and height as Rui, was named Rie Kamishiro, the orange haired girl, who had the same features and height as Akito, was named Akiko Shinonome and lastly, the blue haired girl, who had the same features and height as Toya, was named Tora Aoyagi. It was a strange but also interesting SEKAI…