Kim Jongin believes in love at first sight. He'll be the first to admit that this belief is pretty cliche, but as someone who drowns himself in overly hyped pumpkin spice lattes every fall, Jongin doesn't exactly mind indulging in cliches. In Jongin's heart, it was fate that his alarm clock had rebelliously decided to not wake him up for his 8:30 class, causing him to be excruciatingly late on his very first day of university. How can it possibly be a coincidence that the final unoccupied seat in the crowded classroom is left next to a beautiful (yet kind of scary looking) music education major, who warmly introduces himself as Do Kyungsoo? Jongin is convinced that they're meant to be.

As Jongin falls harder for Kyungsoo over a short amount of time, something starts to feel... off. Jongin isn't the smartest person alive, but he's pretty sure it's not normal to wake up surrounded by flower petals every morning. To make things even stranger, he discovers that the mysterious petals are somehow produced from his very own body, escaping through his lips after long and uncomfortable coughing fits. Jongin frantically searches for answers but finds no information that could possibly explain why he suddenly became a human greenhouse. Will he ever find a cure to the disease that doesn't seem to exist?