A famous influencer, Kang Sol, registers at Hyun Joong's gym, helping the gym to get more members. Hyun Joong isn't glad to see her as she's his ex, and he can't help but think she has an ulterior motive. Sol becomes friends with Mi Ran, and she sets her up on a blind date. After a few dates, Mi Ran realizes her feelings toward Hyun Joong are too strong to meet someone new.

Hyun Joong disappears without a trace, and members of the gym are determined to guard the gym until he comes back. Mi Ran tirelessly searches every place Hyun Joong might have gone. Amid the collective effort to save the gym, Ro Sa hears something utterly devastating. Meanwhile, Ji Ran is having a hard time getting over Dan.