A Childhood Friend and Younger Sister

Hina is torn between her love for her older brother and the impossibility of being with him. In an attempt to find solace, her friend Hana, who is fascinated by the occult, lends her a mysterious crystal that supposedly has the power to switch two people's places for a day. The crystal's abilities prove to be real, and Hina unexpectedly finds herself switching lives with Yui, her brother's girlfriend, leading to a complex and emotionally charged experience.