In the middle of the school caste, the dull faced high schooler, Nishino Gokyou, is the strongest ability user in the neighborhood.
He who is in love with dandyism uses his superpowers and lives for work. While usually going to his completely normal highschool, he is in fact an agent in the underworld whose name is widely known. His name is acknowledged not only within the country, but even overseas.
At the end of the culture festival he accepts a request from his partner Marquis, and it turned out to be a mission abroad. At the same time, Takeuchi-kun takes on the role of a leader and plans a trip abroad with a group of close friends in class 2-A in the name of graduation trip. And by coincidence, they end up leaving Japan on the same flight.
But unexpectedly, a hijack occurred during the flight. By some other coincidence Tarousuke also happened to be on the same flight, and together with Nishino, the problem was resolved. While the hijackers were overwhelmed by his extreme cynicism, the passengers and crew were instead irritated.
After safely arriving at his destination, Nishino meets with Francisca and it ends with the two cooperating. While working together they find out that the target had already been killed, and the one who did it, a lovely girl around the same age as Rose.
That girl’s name is Gabriella.
Just like Nishino, she is the owner of a mysterious power.
During their encounter with Gabriella, a large scale battle broke out between Nishino and her. It’s then that Rose catches a glimpse of her beloved, and leaving the others from class 2-A, she goes to Francisca and Nishino. This ends with them moving together.
At the same time, the class rep separates from Takecuhi-kun’s group, and after getting lost in the island she is helped by Nishino’s group, and now she also goes along with them.
Having unexpectedly met with Nishino, Rose requests to conduct her originally planned sightseeing tour of Santorini. Nishino hesitated, but unable to avoid Rose’s help with the class rep, the two do as Rose wanted and they began their sightseeing.
Meanwhile, Gabriella was in ecstasy after meeting Rose.
She is a hardcore homosexual.
Wanting to obtain Rose no matter what, Gabriella makes use of some underlings to kidnap Takeuchi-kun’s group who Rose had been with, and making use of the groups belongings, they plan to lure Rose in.
Tarousuke who happened to be passing by tried to help, but it’s to no avail as he is also captured.
At the same time, Rose and Nishino are completely ignorant to the fact that their classmates had been captured due to Gabriella’s scheme, and they continue on their sightseeing of Santorini along with the class rep. This applies especially to Rose, as this is the long awaited trip with the one she loves.
And it’s then, that Rose gives Nishino a proposal.
If in the span of three months Nishino doesn’t falls for Rose, then the latter will disappear from the former’s sight, and never appear before the other again. On the other hand, if Nishino relaxes his guard against Rose even a bit, that body will become the other’s possession.
Not even considering the thought that he would relax his guard against Rose, Nishino readily accepts.
And so begins the three month long battle.