One day, suddenly, an angel came descending from the sky!?
While heading towards his university entrance ceremony, Yuu meets an unsociable, mysterious girl. Yuu, who can’t help but be curious of her — who is as free-willing as a stray cat — gradually shortens the distance between them. As various feelings mix around, their bond gets spun together, but what can be seen beyond that is…
The story follows Kaizaki Arata, a 27-year-old jobless man who fails at every job interviews he had after quitting his last company which he only last three months. His life changes after he met Yoake Ryou of the ReLife Research Institute, who offer him a drug that can change his appearance to 17-years-old again and to became a subject in a one-year experiment in which he began his life as a high school student again.