Dear Dolphin (2013)

One summer night, Cha-kyung dies by a car accident, leaving her boy friend Hyuk-geun behind in the greatest sorrow. One year since she died, Hyuk-geun is still waiting for Cha-kyung to come back. Denying the reality, Hyuk-geun builds a fantasy in his mind where he and Cha-kyung secretly share the everyday life. To wake up Hyuk-geun from Cha-kyung's illusion, Cha-kyung's best friend, Gi-ok who was secretly in love with him, puts herself in the same accident with Cha-kyung.