It’s a romance centered on genuine affection. Go Mi Ran and Ma Dong Chan become involved in an experiment that dramatically alters their lives. The narrative is skillfully crafted, featuring characters who are thoroughly realized. It delivers a charming romantic storyline alongside an engaging mystery element. I was kept intrigued throughout, and the secondary storylines enhanced the central plot. Both the male lead and female lead were superb; their on-screen connection was exceptional. The gradual development of their romance felt authentic and rewarding. Go Mi Ran stands out as one of the most memorable female characters I’ve encountered in a Korean drama—spirited but not grating, displaying both assurance and resilience. The performers did an impressive job portraying their roles, and the ensemble cast was solid overall. I strongly suggest watching it, having viewed it at least five times. While I share the sentiment of others regarding a somewhat disappointing conclusion, that seems to be a frequent occurrence in Korean dramas.

Source on TMDB