When her daughter is assaulted at school, a furious Jeong Hui-ju confronts the teacher who is responsible. She's reminded of someone she used to know.

An Li-sa wakes up her family in the middle of the night in a panic. Hui-ju can't shake the suspicion that Gu Hae-won's reappearance isn't mere coincidence.

Years ago, a fast friendship formed as Hae-won gave Hui-ju drawing lessons. When an emergency came up one day, Hae-won sent in a substitute teacher.

The possibility of Seo Woo-jae's return places Hui-ju further on edge. Lee Ju-yeong hands Hui-ju her old cellphone.

Reunited with Woo-jae at the opening of his art exhibit, Hui-ju learns why he disappeared for so long. Hae-won consults a doctor about his condition.

Increasing encounters with Woo-jae, as well as unsettling run-ins with Hae-won — who seems to know a damaging secret — shake up Hui-ju.

The art gallery makes a new hire and asks Hui-ju for a favor on an upcoming project. Hae-won's mind is set on having the wedding she always wanted.

An old sketchbook Hui-ju thought she destroyed turns up again. Hae-won stands up for Ju-yeong's family against An Hyeon-seong.

A forbidden tryst at the wedding has an unwitting witness. Hui-ju finds out something that Hyeon-seong has been keeping from her.

Hae-won experiences a sudden loss. Woo-jae tries to make sense of his fragmented memories. Hui-ju prepares for her son's birthday party.

An Ho-su's kidnapping stirs up panic in Hui-ju and Hyeon-seong, who each have their own suspects. Hae-won leaves a mysterious envelope for Hui-ju.

Hyeon-seong shows Hui-ju that he will allow nothing to come between their marriage. In search of all he's lost, Woo-jae sets off back to Ireland.

Hui-ju feels cornered when her mother-in-law acquires Ho-su's birth certificate. Woo-jae returns from his trip with a question for Hyeon-seong.

Hui-ju exits her art collaboration with Woo-jae and responds to an alarming call from Li-sa's teacher. Hae-won is found in a worrying state.

Hui-ju finds herself in her darkest hour yet. When Hae-won reveals she was there the night of the incident, Hui-ju runs out of options.