He risks his life to save his sister's life. But he knows something is off as he faces obstacles every time he does something for his sister.
She knows he is plotting something, but she hesitates to find that out and accuse him. After all, he saved her life when she was kidnapped.
(spoiler)
Natsuki (played by Kuroki Meisa) and Kentarou (played by Hiraoka Yu'uta) realize that whenever Natsuki has two sets of memories, Shu'uya is in the scene. They start to check on Shu'uya.
They even sneak into Shu'uya's office. Natsuki hesitates and tells Kentaro to stop doing things behind Shu'uya. Obviously, she does not want to think Shu'uya is a bad guy.
They find out that Shu'uya got his position at their university to get close to Natsuki.
Natsuki's mother goes to see Shu'uya. Fifteen years ago when Natsuki was kidnapped, Shu'uya made her promise to get a marketing approval for the new drug she was developing by 2007 in order to save Natsuki's life. She tells him she fulfilled the promise so he shouldn't bother her and Natsuki again. He tells her he won't hurt them.
What actually happened was that in order to get an approval she hid the information on a side effect. In a very rare case, a person may die when he/she takes the drug with alcohol.
Mami (played by Taketomi Seika), the violinist and her older brother Shu'uya are invited to Kentarou's parents' place. Shu'uya works overseas and happened to come to Japan this time. This Shu'uya looks different from Professor Shu'uya. The former is a younger Shu'uya of the present day while the latter is an older Shu'uya from the future.
Kentarou's mother shows him a picture of Mami and Shu'uya. Kentaro and Natsuki find out the relationship between Mami and Shu'uya. Mami's last name is Mi-Tsu-Ta. If this name is written backward it becomes Ta-Tsu-Mi, which is Prof. Shu'uya's last name.
Mami is told that she has a visitor named "Kentarou". She gets excited to see him, however he came with Natsuki to ask her to let them meet her brother. Seeing that Natsuki and Kentarou are in a very close relationship, Mami is heart broken. She drinks wine and takes her medication (the drug developed by Natsuki's motoher).
The more Kentarou tries to investigate Shu'uya, the farther the distance between the two becomes. After all, she can't hate Shu'uya and knows he's doing things all by himself. Also, she knows she is a burden to Kentarou as he thinks he is to blame for her kidnapping. Their relationship is strained.
Shu'uya has been having a heart problem. It is perhaps the result of his time travel. Natsuki finds Shu'uya lying on the floor in his office. He was going to go to Mami to stop her from taking alcohol.
Natsuki takes Shu'uya to Mami. Mami passed out on the floor. Shu'uya asks Natsuki not to have Mami sees himself (= Shu'uya from the future). Mami is taken to a hospital.
Shu'uya wonders why Mami dies every time he time-travels and tries to save her. Through his talk with the physics professor Natsuki is working for, he finds out that even if he tries to change the course of fate, there is always a strong force to make things back to where/how they were before the change.
He also finds there is an obstacle which always prevents the course of change. That obstacle is something that should not exist from the first place. In his case, that obstacle is Natsuki.
Time Spiral Ep.4
Time Spiral Ep.3
Time Spiral Ep.2
Time Spiral Ep.1
Time Spiral Premiers on Sept 2
Time Spiral
