X's partner

Taejin, who was gaslighted and ultimately dumped by the partner he trusted during his idol trainee days, barely manages to debut. However, things take an unexpected turn when Jaerim—his ex’s former partner and the person responsible for the gaslighting—joins the group as a new member. Taejin, who is subtly avoiding Jaerim, who is successful and popular with everyone, soon becomes entangled in rumors of discord. Jaerim claims that Taejin is the cause of the rumors, while Taejin insists it’s all a misunderstanding. To clear up the discord, the two of them are subjected to a special measure.