Season 01

A lonely teen meets a mysterious neighbor who knows his birthday—then vanishes without a trace.

Documentary charting rival attempts to reach absolute zero, the ultimate limit of cold, by scientists in London and Leiden. A second race unfolded 100 years later, towards the end of the 20th century, as scientists atte…

Onsa and Suansoon grow closer through movies and late-night talks, blurring time and emotion.

As Suansoon moves to a new apartment, he meets another student next door—just like before.

Onsa plans a secret outing for Suansoon as their days together near a quiet, tender end.

Suansoon disappears after leaving Onsa a letter, sparking a desperate and tearful search.

At the theater, Onsa meets Suansoon for the “first” time—two souls crossing through time.

As graduation nears, Onsa and his friends share one last night at Nan’s café before goodbye.

In 2018, Onsa’s accident stirs memories from 2008—where fate links him to the name “Suansoon.”

Onsa reveals his name and leaves a letter for Suansoon as the school’s film night begins.

Suansoon chooses a new path—and a familiar voice answers when he calls about a vacant room.