Ten people are given the chance to go back in time by one year and reset their lives. But as their altered fates begin to twist in unexpected ways, mysterious events start to unfold.

Ji Hyung Joo, a laid-back but skilled detective in the violent crimes division, once rose through the ranks after capturing a wanted criminal. At first, he's thrilled to rewind time and make different choices—but when members of the group begin facing strange and deadly consequences, Hyung Joo realizes something darker is at play.

As the past unravels, he must uncover the truth before time runs out again.