Nagi Shiratori is the only daughter of a large company, the Shiratori Group, she is feared because of her family background and is looked away from by her classmates. One day, however, she is suddenly asked by a stranger, a male student, to become “engaged” to him, and Nagi is perplexed. She is rescued by a beautiful young man named Rei Kuroshima, who for some reason claims to be “Nagi's boyfriend” even though they have never met before. In fact, Kuroshima says that he was sent as a guard to protect Nagi from those who are after her fiancé. In order to avoid being targeted by others, the two pretend to be friendly “lovers” at school! On the outside, Kuroshima plays the role of a sweet boyfriend, and on the inside, he teases the confused Nagi.
However, behind the scenes, Kuroshima is hiding his growing feelings for Nagi!

A high tension reversible love comedy where love starts from a lie!
突然やって来た美形男子は、私の専属護衛で……彼氏！？

大企業《白鳥グループ》のひとり娘・白鳥凪(しらとり なぎ)は、
その家柄を恐れられ、クラスメイトからも遠巻きにされる日々を送っていた。
しかし、ある日いきなり見知らぬ男子生徒に”婚約”を迫られ、困惑する凪……。
彼女を助けたのは、なぜか初対面なのに「凪の彼氏」を名乗る美青年・黒島玲(くろしま れい)だった。

実は、婚約者の座を狙う者たちから凪を守るため、護衛として派遣されたという黒島。
周囲に狙われることがないよう、学校では二人で仲睦まじい「恋人同士」のフリをすることに！
オモテでは甘々彼氏を演じ、ウラでは戸惑う凪をからかう黒島。
しかし、そのさらにウラには、凪への募る想いを秘めていて――！？

嘘から恋が走り出す、ハイテンション・リバーシブル・ラブコメディ！