Storyline:

A secret high school romance unfolds as 'Outsider,' the new manager of the anonymous app 'Inssa Time,' gains access to the school's secrets and mingles with a group of super popular kids. Among them is Kang U Bin, a top student and trainee idol admired by all. Despite his perfect image, U Bin harbors a hidden secret that 'Outsider' unwittingly threatens to expose.