Kazuya Kinoshita, 20, has a great girlfriend named Mami Nanami who is cheerful and sunny. That is until one day when he is abruptly dumped, leaving him completely sad and alone. He uses an app to find a rental girlfriend in an effort to ease the pain. His companion is Chizuru Mizuhara, who charms Kazuya with her unrivaled beauty and sweet personality. Kazuya, however, thinks Chizuru's pleasant smile and caring nature were all simply a act to play with his heart and he evaluates her poorly after reading similar experiences other clients had had with her. Angered, Chizuru blasts him for his blatant hypocrisy while displaying her actual pert and irritable personality. However, Kazuya interrupts this one-sided conversation when he learns that his grandma had collapsed. As they race to the hospital, they discover Kazuya's grandmother already to be doing well. She wonders who this girl might be and is perplexed by Chizuru's presence. In an instant, Kazuya declares that they are in love.