"When a Man Falls in Love" Shin Se Kyung gets an insight into Yeon Woo Jin's dark side.

May 30, the 18th episode of the MBC drama "When a Man Falls in Love" featured Lee Jae Hee (Yeon Woo Jin) revealing his secret plans of destroying Han Tae Sang (Song Seung Hun) to Seo Mi Do (Shin Se Kyung).

Han Tae Sang tries to tells Lee Jae Hee about the secret left behind by Lee Chang Hee (Kim Sung Oh). Han Tae Sang says, "Come to my house after work" but Lee Jae Hee replies, "I don't want to go." Lee Jae Hee believes that it is another one of Han Tae Sang's plans to hurt him.

When Lee Jae Hee refuses to listen to him, Han Tae Sang goes to Seo Mi Do to show her the letter written by Lee Chang Hee. The next day, Seo Mi Do tells Lee Jae Hee, "I saw the letter that Mister Chang Hee wrote. Why are you avoiding Han Tae Sang? Why don't you just check the letter and see if it is really Chang Hee's writing?" Lee Jae Hee replies, "It's too much even just to see him."

In Lee Jae Hee's car, Seo Mi Do finds an envelope with DNA testing results. Seo Mi Do asks, "Did you get a DNA test already?" but Lee Jae Hee answers, "It's not mine." Lee Jae Hee tells Seo Mi Do that he found Han Tae Sang's little brother then reveals his plans to destroy Han Tae Sang.

Seo Mi Do is completely shocked and tells him, "How could you do that? You can't mess around with family. Go tell him that you found his brother right away." Lee Jae Hee replies, "Who's side are you on?" Seo Mi Do becomes very disappointed after seeing the dark side Lee Jae Hee has been hiding.