One loves too much.. to unlove.   

The flower petals, slowly filling his lungs and blooming in his throat were choking him. Tears finally streamed down his cheeks indicating that he couldn't bear the pain. Youngho had suggested him to undergo the surgery. But the only thing running inside his mind was that the pain was worth it, Yuta was worth it.

Jackson finds himself constantly coughing up flower petals, while Mark remains oblivious to his best friend and roommate's unusual health condition.

Hanahaki Disease is an illness born from one-sided love, where the patient throws up and coughs of flower petals when they suffer from one-sided love. The infection can be removed through surgery, but the feelings disappear along with the petals. Woozi has the Hanahaki Disease. He just got it and is puzzled as to why he has it. Then he sees a Seungcheol being all sweet and well, Seungcheol, he feels the urge to puke more petals. His petals were all blue. No other colours only blue.