Lee Sungyeol and Kim Myungsoo have been a friend from they are four years old. Although both know that their love each other, they seems afraid to confess as it would bring damage to their friendship. However, when they are in College, Myungsoo finally confessed to Sungyeol and then they‘re officially dating.

Fate seems not on their side as after they have been dating for a month, Myungsoo has been diagnosed brain cancer. Myungsoo is so sad because there are many things that he wants to do with Sungyeol as a couple. So, starting on that day he has made lists of what he wants to do with his lover before he died.