寝屋川 理央

She is a freshman girl attending school. Her father, a leading pharmacological researcher, passed away several years ago due to illness. She lives a normal life with her father's inheritance, but she does not have a lot of assets because a large amount of money was invested in research funds.

She lives alone with her mother, who is tired of dealing with relatives since her father's death, so she entered a lottery for tickets to the Uzushio. She won a pair of tickets.

Delighted with her daughter's happiness, the mother also asked Ruka, who was present at the opening of the winning ticket, “Why don't you come with us?" (the Neyagawa family pays for Ruka's ticket).

Because her father entrusted his daughter with confidential information, she is targeted by a suspicious person hired by a rival in the pharmacy world, and Planning Section 2 sniffs out the information and plans to snatch it from the side. Rio's childhood friend, Ruka, is her confidant and sister.