Kiu meets Ek and is challenged to beat him in 21 days—sparking rivalry and unexpected bonds.

After Ek’s injury, Kiu tends to him closely, giving them a chance to see each other differently.

As their days together grow, Kiu’s feelings shift, and mutual understanding slowly deepens.

At a turning point, Kiu and Ek must face whether the “21-day theory” will define their future.