South Korean film “Vanishing Time: A Boy Who Returned” is a fantasy melodrama constantly swinging between its dark premise and sentimental mood. Although the mysterious situation surrounding its young heroine has inherently uncomfortable aspects for good reasons, the movie believes in its premise as much as her, and it manages to earn a fair share of weepy moments as earnestly pushing its premise to the end.

When Soo-rin (Sin Eun-soo) arrives at some big offshore island along with her stepfather, she does not look that happy about this removal. Since her mother’s recent death, she and her stepfather have been more estranged from each other than before, but he tries to make her feel comfortable at least, while beginning his first working day at a tunnel construction site in the mountainous region of the island.

As the new student in a local elementary school, Soo-rin does not get along well with her schoolmates, and she is ridiculed for her personal interest in supernatural phenomena, which was probably originated from her grief over her mother’s death. Fortunately, she befriends an orphan boy named Seong-min (Lee Hyo-je, who previously played a minor supporting character in “The Throne” (2015)) after their accidental encounter in front of the school, and he soon becomes someone with whom she can share her fascination with those preposterous things like out-of-body experience. As they spend more time together around the island, they happen to discover a shabby abandoned house located within a mountain forest near the tunnel construction site, and it quickly becomes their own private place as they feel more of the innocent affection being developed between them.

And then something very strange happens during one fateful day. Soo-rin goes into the forest along with Seong-min and his two friends for watching the detonation process at the tunnel construction site from the distance, and they come across a small, narrow burrow somewhere in the forest. Although it looks dark and ominous to say the least, they eventually crawl inside the burrow and then arrive at an underground chamber with the pond containing a mysterious shining object. After they come outside with this object, they become more curious about it, and Seong-min tells others about a weird story he heard from his grandfather before. Is it possible that the burrow is the one described in that story? And does the object in question really belong to a ‘time-eating monster’?

Anyway, not long after Soo-rin goes back into the burrow to find her lost hairpin, Seong-min and two other boys are vanished without any trace, and this incident surely shakes up the whole island community. As the search around the island is continued without any success, there comes a grim possibility that the boys will never return – especially after a terrible discovery on the beach.

While understandably shocked and devastated, Soo-rin also becomes more frustrated because nobody believes her story, and then a more unbelievable thing happens to her. When an unknown man breaks into her house while she is alone at one point, she follows after him as he runs away into the forest, but then she finds herself getting caught by this guy. He claims that he is none other than Seong-min, but, of course, Soo-rin does not believe at all what he desperately tries to tell her, and he is soon hunted by the police as the prime suspect.

However, after the discovery of a definite proof she cannot deny, she comes to see that he is really Seong-min, and the following flashback part gives us the glimpse into an amusingly odd but ultimately despairing circumstance in which Seong-min and two friends were trapped for more than 15 years. They initially had a fun with a sort of alternative world where everything including time was stopped except them, but they eventually became more acutely aware of the horror of their possibly infinite isolation in the dimension of time and space, and that leads to some of the most poignant moments in the film.

Now played by Kang Dong-won, Seong-min is not a little boy he used to be, but Soo-rin still sees his younger self from Seong-min’s changed appearance. While Kang’s boyish looks effectively convey the innocence remained intact inside his character’s adult body, his co-star Sin Eun-soo’ strong performance firmly holds our attention as the emotional anchor of the story, and we become more involved in Soo-rin’s desperate attempt to save her friend during its second half. Clearly identifying with their desperation and frustration, the movie also lets us understand why the other characters in the movie regard Soo-rin and Seong-min’s situation quite differently. Yes, they could consider her rather improbable story more seriously, but even she did not trust him at first. And, after all, who can possibly be unsuspicious about the sight of an underage girl being closely associated with an unknown man who looks more than 25 at least?

Although I have some reservation on several shaky aspects of its premise, that remains a minor flaw at least, and there is enough amount of sensitivity to engage us in “Vanishing Time: A Boy Who Returned” mainly thanks to the director Eom Tae-hwa and his two dependable lead performers. This is sappy indeed, but it is sincere about their extraordinary circumstance, and we come to care more about them as following their desperate drama – and that is what a good melodrama movie is expected to do, you know.