Coming-of-age drama about 18-year-olds, taking a realistic look into the moments of their lives, moments that all of us might have experienced at one time or another. Ong Seong Woo plays Choi Jun Woo, for whom loneliness has become a habit. Though Choi Jun Woo appears to lack empathy at first glance, it’s just that he has always been alone and isn’t practiced in expressing his emotions. Underneath his withdrawn exterior is a goofy and cute young man. “18 Moments” is about the events that unfold when Jun Woo transfers schools and is thrown into a new environment.

On-yoo is an adult childhood cancer survivor. When he's not practicing with his boy band, Oh-yoo often volunteers at the hospital's pediatric cancer ward. One day, he recognizes the familiar face of an overdose patient.

A man's affair with his family's housemaid leads to a dark consequences. Eun-yi is hired as an au pair for Hae-ra (pregnant with twins) and her rich husband Hoon. Eun-yi's primary task is watching the couple's young daughter, Nami. Eun-yi is eager to connect to Nami, who gradually warms to her. Hoon begins to secretly flirt with Eun-yi, enticing her with glasses of wine and his piano playing, and they eventually begin a sexual relationship. Despite the affair, Eun-yi is still warm and friendly to Hoon's oblivious wife, Hae-ra. She even expresses enthusiasm and delight at the progress of Hae-ra's pregnancy.