Sunny

Na-mi, a wealthy but depressed housewife, eats breakfast alone every morning and feels emotionally distant from her family. She longs for connection and meaning beyond her pristine life. This opening moment sets the tone of her quiet dissatisfaction with the façade of perfection.

During a visit to her mother's hospital, Na-mi spots a patient room bearing the name Ha Chun-hwa, and the memory of her high school days comes flooding back. The name acts as a catalyst that pulls her toward the past she left behind. This moment marks the transition from present to flashback.

In the past, Na-mi is introduced as a new student at an all girls high school in Seoul. She is ridiculed for her country accent and appearance, but her encounter with Ha Chun-hwa soon earns her a place in Sunny. The group comprises several friends and becomes her new circle as she navigates teenage life.

Na-mi bonds with Chun-hwa and officially joins the six member group Sunny, alongside Jang-mi, Jin-hee, Geum-ok, Bok-hee, and Su-ji. Together they share adventures and form a tight knit alliance, even as a rival group from another school challenges them during a police riot. The early camaraderie foreshadows the enduring ties they'll later fight to preserve.

Na-mi experiences her first love with Han Joon-ho, a boy connected to Jang-mi's circle. Her feelings are unsettled when she sees Joon-ho with Su-ji, leaving Na-mi with heartbreak and confusion. This romantic thread complicates her sense of belonging within Sunny.

Back in the present, Na-mi learns that Chun-hwa is terminally ill and decides to reunite Sunny before it is too late. She resolves to bring the group back together, honoring Chun-hwa's memory through their friendship. The news acts as a catalyst for a multi decade plan to reconnect.

With help from her old teacher and a private detective, Na-mi locates each Sunny member and discovers where they are now. Jang-mi is a struggling insurance agent, Jin-hee is an elegant wife with a cheating husband, Geum-ok is unemployed, Bok-hee has turned to prostitution, and Su-ji remains elusive. These portraits show how far they've drifted from their teenage selves.

Na-mi finally locates Han Joon-ho and confronts the unresolved feelings from their youth. The encounter gives her emotional closure and strengthens her resolve to reunite with Sunny for Chun-hwa's sake. She returns to the plan with renewed purpose.

In flashbacks, Sang-mi, a jealous rival, torments Na-mi, but Su-ji intervenes to save her. The incident helps cement the bond within Sunny and foreshadows the group's lasting loyalty. The rescue also paves the way for Su-ji to become part of the circle.

During the school annual festival, Sang-mi's control spirals, Chun-hwa steps in to defend Na-mi, but Sang-mi injures Su-ji with a shard of glass. Su-ji is rushed to the hospital and the Sunny girls are beaten by the principal. The event marks a brutal turning point in their teenage years.

That night, Na-mi and the Sunny members gather in front of Su-ji's house, and Chun-hwa urges them to join hands and promise they will meet again in the future. The vow becomes a guiding thread that will pull them back together years later. It is a poignant moment of unity amid uncertainty.

Chun-hwa passes away before the reunion, but the women rekindle their friendship and confront new challenges including revenge on a bullying group targeting Na-mi's daughter. At Chun-hwa's funeral they all attend except Su-ji, who is later invited publicly by a newspaper notice. The lawyer reads Chun-hwa's will, revealing meaningful gifts and opportunities for each Sunny member, and they celebrate with a dance to their old routine as Su-ji makes a surprise appearance, ending with nostalgic flashbacks to their teenage years.