I have not watched the original Korean series, but I have thoroughly enjoyed this Thai remake. The story may not be original, but the delivery of the story is really good.

The story starts with a police officer (Peera) traveling (roughly) thirty years into the future (from 1985 to the 2010s) while trying to nab a serial killer. He helps to solve other cases in the 2010s before being confronted with the serial killer again.

The characters and their relationships are interesting, especially the relationship between Peera and Thanthai (a police officer in the 2010s, the son of one of the serial killer's victims). The cast is excellent; the actors for even relatively minor characters turn out a riveting performance.

Some time travel paradoxes are present, and this is somewhat inevitable. However, one weakness lies in the suggestion that when Peera gets back to his original time in 1985, what he does can change the future, e.g. the present-day serial killer has a new memory of being chased by Peera in 1985 after Peera gets back to the past and tries to catch him. This should also mean that if Peera manages to get back to 1985 and nab the serial killer, the subsequent killings after 1985 can be prevented. It then becomes baffling that he does get back to 1985 permanently in theend, but there is nothing to suggest an attempt to nab the serial killer and prevent the killings that would occur in the 1990s to 2010s. (This is disturbing because most of the killings are actually done after 1985.)

Furthermore, because Peera eventually gets back to 1985, it could mean that the death of his wife (a few years after 1985) in an accident can be prevented, and his daughter won't be orphaned. This may well mean that the orphaned daughter may have a different career and may not help the police of the 2010s solve the serial killer case. In fact, all the events that lead to the nabbing of the serial killer in the 2010s may be changed because Peera returns to 1985 in the end. This then means that the effort Peera puts in to nab the serial killer in the 2010s are likely to be futile unless he doesn't return to 1985.

I guess the ending in which Peera returns to 1985 is aimed to be pleasing enough to most audiences even if it is at the expense of logic. It would indeed be too heartbreaking an ending if Peera doesn't return to 1985 when his wife is waiting for his return. Additionally, people may not like seeing the 2010s characters they have grown to be familiar with suddenly reconfigured by Peera's return to the past.

Personally, I think a reconfiguration could have been done: Peera can nab the serial killer in 1985, preventing more killings. His wife may avoid the accident causing her to die. His daughter doesn't have to be orphaned, but she can still be a professor of criminal psychology and help the police solve crimes. Thanthai (the police officer who happens to be the son of one of the killer's victims may not become a police officer but instead be a doctor/forensics doctor (he gives up studying medicine to be a police officer in order to catch the serial killer). The drawback, of course, is that the audience have spent too much time with the original 2010s characters and their particular histories to be comfortable with their histories rewritten in half an episode or less. But this seems inevitable: e.g. why would Peera's daughter be orphaned if he returns.

While the flaws of using time travel as a plot device are not entirely negligible, the series is still satisfying. The characters and their relationships are engaging without being a distraction from the crime cases. Despite not getting a lot of screen time, the love between Peera and his wife, Wad, is touching. The bond and sometimes tensions between the police officers (Peera/Suchart, Peera/Thanthai and the 2010s team in general) are effectively portrayed without much distraction from the crime stories.

In the end, I still wish that there is a clearer explanation of why the main serial killer changes the sort of targets he had in the 1990s. In fact, I would probably prefer having Peera change the "original" future by going back to the past and nabbing the serial killer. But taking the story for what it is, it is hard to fault the delivery. I'm glad seeing Peera going back to 1985 and having a happy ending. The possibility that his eventual return to 1985 would change the future that he has experienced (including the nabbing of the killer) seems to have been totally ignored in the end, perhaps because the ending isn't meant to trigger a Season 2. If we really demand something that is entirely logical, we are probably better off avoiding time travel stories.