Part 1: Yoon Tae Yi and Yoo Min Hyuk time travel from 2050 to 1992 and recover the "Book of Prophecy," a book that reveals the tragic end of time travel. However, Tae Yi finds out she is pregnant and decides to stay and have the baby by herself. She changes her name to Park Sun Young and gives birth to Jin Gyeom, a boy who grows up lacking pro-social emotions. Part 2: After celebrating his mother's birthday, Jin Gyeom finds his mother dying on the floor. Her death hits Jin Gyeom hard, and he decides to become a police officer. Now in 2020, Lieutenant Park Jin Gyeom takes on a case where a kidnapped child claims she was with her mother from the future.

Part 1: After chasing down a suspicious drone, Jin Gyeom thinks he sees his mom and suddenly gets hit by a car. He's not the only one who claims to have witnessed a drone, and strangely, reported sightings all occur at odd crime scenes. Jin Gyeom continues to work a kidnapping case involving a mom from the future, hoping it will lead to seeing his mother one more time. Part 2: A time traveller out to get revenge escorted by Alice, an organization providing time-travelling services, commits murder in the past. Jin Gyeom chases him down but loses him. When Alice tries to ban him from future time travels, he takes down an Alice guard and makes his way back to the past and knocks on Jin Gyeom's door.

Part 1: Agents from Alice try to recover the time card in Jin Gyeom's possession. But they don't realize he has two of them. Jin Gyeom, who thinks Tae Yi is his mother from the future, asks her to take a look at the bizarre card to see if she can figure it out. Meanwhile, Jin Gyeom looks into Tae Yi's family. Part 2: A desperate mother from the future takes drastic measures to stay with her child. Although she successfully retakes her past life, it puts the child's life in danger and exposes time travel. Meanwhile, the card Jin Gyeom gave to Tae Yi does something strange in front of her eyes and finally gets her attention.

Part 1: Captian Ko recovers in the hospital after getting stabbed by the desperate mother who gets away with her daughter. However, Alice agents and Jin Gyeom track her down. Sergeant Dong Ho manages to handcuff Alice agent Min Hyuk, but he disappears into thin air. Meanwhile, Tae Yi goes through Jin Gyeom’s late mother's possessions for additional clues and tells Jin Gyeom she was never just an ordinary housewife. Part 2: Tae Yi begs Jin Gyeom to let her continue investigating the card, but he won't let her even touch it. Jin Gyeom meets with Seok Oh Won, a director at a research facility, and suspects him to be his mother's murderer. Meanwhile, a drone appears outside Tae Yi window.

After the accident, Jin Gyeom finds himself talking to Tae Yi in the year 2010. He calls his mother and warns her not to leave the house, but it's already too late. As he witnesses her dying again, she sends him back to the present. Meanwhile, Alice takes note of a time travel glitch and plans to bring Jin Gyeom to Alice.