Moon Ji Yong, the actor playing Jae Woo, looks particularly good when he smiles, but he doesn't smile very often in this series. It's perhaps very astute casting as the contrast between the moody Jae Woo and the person he could possibly be if not for what has happened to him at the age of ten.

What sets this series apart from many BL series is the way the sweetness of the couple comes with minimal fluff. The cinematography and the music are really commendable, but I wish the editing had sometimes been a little difference. Given how short the series is, there is really no need for scenes to be repeated, such as when Episode 2 doesn't take the story further from Episode 1 but merely provides additional details.

There is a bond between the two main characters that becomes stronger although the bulk of the romance does not take place over a long time frame. Jae Woo's first feelings are gratitude towards Ji Hoon for saving him when he is young and remorse about how Ji Hoon has sacrificed his life to save him. However, when he travels back in time as an adult to the time he is ten, his romantic attraction to Ji Hoon is quickly apparent. Yet, it is obvious that the time the couple has together is limited.

When it dawns upon Jae Woo that he can perhaps do something to save Ji Hoon, the situation does not become much more hopeful. First of all, there is the likelihood that Jae Woo is unable to change the past and save Ji Hoon. Secondly, if he does, we will end up with a paradox: if Ji Hoon does not die, then adult Jae Woo will not travel back to the past and meet Ji Hoon in the first place. In short, a happy ending for the couple seems unlikely. Still, one hopes . . .

Spoiler:

In the end, Ji Hoon discovers that adult Jae Woo has traveled back in time and is trying to save him. However, he decides not to be saved because his logic is that if he doesn't die, then Jae Woo the kid will die (with no one to save him) and the adult Jae Woo who travels back in time and falls in love with him won't exist. (But if so, who will travel back in time and save him then? It's one of those paradoxes of time travel stories that one should probably not think too much about.)

Perhaps in a bid to soften the impact of a sad ending, there is the suggestion (which does not make a lot of sense) of time infinite loop and/or split timelines. It more or less goes like this: the Jae Woo we see throughout the series (let's call him Jae Woo A) goes back in time and does not save Ji Hoon, but because of JW A's time travel, we already have a slightly different version of the past. This means that a split timeline emerges with the Jae Woo who is saved when Jae Woo A travels back to the past, so there's a Jae Woo B (who has slightly different childhood experiences from Jae Woo A). Jae Woo B will grow up and then travel back to the past and meet Ji Hoon in this split timeline, and this will lead to the creation of yet another timeline with Jae Woo C and so on.

I don't know if this really softens the impact of the sad ending for the couple. After all, it would seem that there can be infinite versions of the Jae Woo/Ji Hoon tragedy.

If I get my way, I would simply have the adult Jae Woo helping Ji Hoon save the kid Jae Woon. Let the two grown men fight and overpower the killer. They can even call the cops beforehand or something. And then the kid, who is saved, can be told what to do to travel to the past when he grows up.