After entering high school, the ordinary girl Shinohara Erika (played by Fumi Nikaido) often gets together with fashionable friends to talk about boyfriends. Although she is boastful, Erika has never had a boyfriend. In order to make up for the lie, she had to ask her friend Mita Ayumi (played by Mugi Kadowaki) for help. In order to dispel her friends' doubts, Erika secretly took a photo of a handsome guy on the street and lied that he was her boyfriend. Unexpectedly, this handsome guy turned out to be Kyoya Sada (played by Kento Yamazaki), the number one handsome guy in Erika's school! In order to continue the lie, she could only beg Kyoya to pretend to be her boyfriend. Fortunately, Kyoya agreed at once, but Kyoya, who seemed gentle and sunny, was actually a mischievous and black-bellied big boy. He proposed to let Erika become his loyal dog as a reward for pretending to be her boyfriend. The girl is already in a dilemma and can only beg for mercy from Kyoya against her will... This film is adapted from the manga of the same name serialized by Ayuko Hatta in Bessatsu Margalet from 2011 to 2016.