|Appearance||Period 34 & Period 35|
Rui is a young girl with loose shoulder-length hair and bangs split at the corners with the middle brushed aside. She has big, sad looking eyes.
As a young girl, and as shown in the future, her hair was cut to neck-length.
Rui is a friendly, but easily distressed young girl who often stresses over her decisions and is often left with regret. She is fairly reserved and meek, but if teased she can become stubborn and go into denial.
Heavy with remorse, Rui runs up to the rooftop of her school to mourn her decision of confessing to her long-time friend Kei. She is angry by his rejection considering how hard it was for her to do- and now that he's been avoiding her it makes the pain even worse. Knowing about the rumor of the ghost, who possesses a clock capable of time travel, she begs for it to appear as the clock strikes noon; and in a flurry of uneasy crows, she is shocked to find the Hell's Clock and asks for it to take her back to the prior day.
Being taken back to the moment when she confessed to Kei, Rui is easily able to cover it up by saying she only wanted to ask him to call her when he visits during winter holiday. While she is unhappy, she will need to settle for letting her feelings be unknown.
She tells her less-than thrilled friends the following day, and states that she is no longer into him anyway. The day carries on as normal and a party is held for Kei's departure, with Rui trying to ignore her feelings and sadness. But in the process of doing that they get into a dispute when he offered to help her try to hook up with the crush he's heard about her having. Unaware that it was himself, his playful nature caused her to angrily tell him off, and she is left in tears once again.
The next day she tries to sleep in to avoid having to see Kei again, but remembering the Hell's Clock she considers using it until seeing some flowers on the grave her deceased dog rests. She asks about it and her mother reveals Kei stopped by earlier with them, causing her to remember the day Jiro was buried and how she was unable to stop crying over his death, blaming herself for it. Kei had managed to cheer her up and Rui realizes that while she might get hurt, she can't keep lingering on the past- if she can't move on then things will never change. Grabbing something, she takes off for the bus stop that Kei will be departing on.
Upon spotting him, Rui runs further on the path and calls out to him. Deciding not to use the clock any longer she pulls it off, about to confess to him. But to her shock a truck suddenly flies down the street towards her and she is thrown to the ground. Everyone surrounding them panics as it dons on Rui that she is safe: because Kei pushed her out of harms way. She can only stare in horror at his bloodied, dying body and screams in horror.
A year passes and Rui hurriedly takes off after her friends invite her for ice cream. She claims she has plans and apologizes, heading by the fence where she made her ill-fated confession and continues to the rooftop of the school. She comes to the exact spot every day, at the same time, and has been doing so for a year now in hopes of getting the Hell's Clock to work. She wishes she never used it.
After arriving home her mother brings up that Kei's family has decided to permanently move to Hokkaido and sell their home. His mother will be returning a final time to pick up any remaining items she wanted to take, and she asks that Rui stops by to pay her a visit. She agrees, and the following morning she heads to the Mizuhara home and asks to visit Kei's room. Filled with past memories, she cries again until hearing a strange, ticking sound. She gets up to look and finds another Hell's Clock within one of Kei's drawers. Startled, she finds the ghost observing her, and she warns her that she could use it; but only if she gives up something important in exchange.
Rui quickly agrees, and is taken back to the day she confessed once again. She is unable to hold back tears as she sees her now alive friend, but remembering the clock she quickly asks him why he has one. He denies it initially, then confesses that he had planned on using it to see the future, a few years from now. He had been concerned over her and wanted to make sure she was okay. But he changed his mind because he knew she will be fine and didn't want to waste experiencing the future first-hand. Tearfully, Rui knows she must do something to show him that she can be okay, and she loudly confesses her feelings without hesitation. She tells him that it's fine that he doesn't reciprocate though, because she already knows how he feels about her, and now she is okay with that.
Suddenly the ghost girl reappears, having decided to take Kei away as payment for Rui using the clock. Kei is shocked by this and Rui confesses to having used it a couple of times; but she refuses to let Kei -who has his life ahead of him to be happy- get taken away like this and she offers her own life as compensation. She wants Kei to see her as someone who can be strong, and she thanks him for always being by her side. She throws herself off of the railing.
Since that day, five years have passed. Rui is revealed to have been in a coma since then, and every day Kei comes to the hospital to see her. No matter how long it takes, he will remain by her side. She awakens on the anniversary of that day, and they share an embrace.