The Origin of Blossom Development

Jin-Woo and Do-Young, two brothers who became brothers without a single drop of blood related to them due to their parents' remarriage. Do-Young didn't like the fact that his older brother was always perfect to the point of being perfectionist when he suddenly appeared. However, Jin-Woo, who knew that his younger brother's bullying was actually his affection for him, provokes Do-Young, thinking that his feelings will break his perfectionism...

(Source: Mr.Blue, translated)