"Eunho, you're... like an angel, a guardian angel."

Two childhood friends who were each other's number one priorities for 15 years, Seohui and Eunho.

To call it friendship is, well...there's something between the two of their relationship that no one else can interfere with.
Friends, family, soulmates, lovers(?), they kept switching somewhere in between all those, but suddenly, Seohui broke the news, "Eunho, I don't want to see you anymore."

Those words made Eunho's world fall apart.

I can't act oblivious any longer. I'm crossing the solid line which has been drawn by time. Before you disappear from my side. Before I lose you.