Set in a miniature garden that floats in the sky. The floating garden "Itehari" is a prosperous city known as a utopia. The main character, Hinagiku, who was born into a prestigious family and grew up without any inconvenience, longs for the outside world. One day, when the protagonist turns 18, she meets a young man, Yashiro, who has lost his memory and gets involved in an incident containing the truth of this utopia hidden by her parents. What kind of love and truth will Hinagiku, who doesn’t know anything about the outside world, discover in this fleeting beautiful Utopia?