Synopsis
In the year 2050, Alice (temporal agency) specializes in sending clients back through time to see dead loved ones to find peace and closure; they also police time incursions. Alice agents Yoon Tae-yi (Kim Hee-sun) and Yoo Min-hyuk (Kwak Si-yang) travelled to the year 1992 Seoul to search for The Book of Prophecy (a book that predicts the fates of certain people and end of time travel) and found it. However, Lee Se-hoon (Park In-soo), agent of the mysterious Teacher (rogue group that wants to continue manipulating time), found the young Tae-yi and murdered her father for the book. Before her father died, he gave the final page to little Tae-yi before her adult counterpart arrived. Tae-yi and Min-hyuk acquired the book and had local police arrest Se-hoon. When Tae-yi realized she was pregnant, Min-hyuk (the father) encouraged Tae-yi to abort the child as time traveling (radiation) would cause serious defects. Tae-yi then disappeared with the book to carry her child.
Tae-yi would rename herself as Park Sun-young and single-handedly raised her son, Park Jin-gyeom (Joo Won). Born with Alexithymia, he has difficulty recognizing his own emotions and his classmates called him a psychopath. He unknowingly has the ability to manipulate time in life-and-death situations. In 2010, Jin-gyeom found his mother murdered and vowed to find her killer. Orphaned without a family, Detective Go Hyeon-seok (Kim Sang-ho) and classmate Kim Do-yeon (Lee Da-in) looked after him. By 2020, Jin-gyeom becomes a detective under Hyeon-seok and learns about time travelers, Alice, the Teacher, and the truth behind his mother's death.