If you really love someone, you will fight for them till your heart stops beating, right? However for Luhan, even though Sehun didn't fight for him when an evil spirit possessed him, he is still convinced that his ex-boyfriend loves him and goes to ridiculous lengths to try and prove it.

And Sehun has never had the greatest wits, so he doesn't know how to explain Luhan that his beliefs are really just fantasies.

Sehun and Luhan had their future planned out. With college behind them, they could finally be free to do whatever they wanted. Except, the demon that decided to possess Luhan had the worst timing.

Now seized by an evil spirit and unaware of his surroundings, Luhan doesn't realize Sehun couldn't handle it and decided to leave him.

Starting anew, Sehun never expects to encounter the lover he left behind three years later. Luhan looks fine and seems to not remember a thing, except his undying love for Sehun. Thanks to his annoying and terribly useless best buddy and rommate, Hongki, Sehun now has to handle having Luhan under the same roof. 

With only his diary dedicated to his long gone father, Sehun really hopes to find a way around it.

Dear Father, My Ex is Back!