OEC the band but make the main vocalist (KL) and drummer (JS) exes. All is well until Jungeun suggests something game-changing for the band; a possible line-up change. Oh and the exes-turned-bandmates got tangled into acting for a web-drama where they're supposed to act out a deteriorating relationship. They've managed to keep it professional up until they have to act out an argument that hit way too close to home. (and yes, the title's from adventure time)