Meet Kim Joonmyun, an ultra-rich boy who's ultra-bored with life. He's so bored he even picks up one of the girly novels his mom was reading, To All the Boys I've Loved Before. Deciding that it would "spice up his life",  Joonmyun writes 11 letters to some of his closest friends and also to some random guys, sending them out as letters from "Suho", not realizing the gravity of what he's done and how it would affect everything around him.