Gi Seo-jeong unexpectedly reunites with Cha Yoon, his ex of seven years, on a heterosexual dating show. However, after an accident, Cha Yoon has lost all memories of their relationship and returned to the difficult personality he had seven years ago.

Unaware that Seo-jeong is his former lover, Cha Yoon constantly argues with him and even considers him a romantic rival. Exhausted by their repeated conflicts, Seo-jeong decides to ignore him until filming ends.

But Cha Yoon gradually begins acting strangely. He becomes jealous, repeatedly asks why Seo-jeong never sends him messages, and starts choosing him on the show.

As Cha Yoon’s forgotten feelings begin to resurface, Seo-jeong must figure out what his mentally seven-years-younger ex truly wants before their time on the program runs out.