Ma Dong-chan (Ji Chang-wook) and Go Mi-ran (Won Jin-ah) take part in a 24-hour experiment where both are frozen. Things don't go as expected and they wake up from the frozen capsule 20 years later instead of 24 hours. In order to survive the side effects of their cryogenic sleep, they must follow a set of restrictions to maintain their body temperature at 31.5 °C (max. 33 °C/88-91 °F) and keep their heart rate normal. The scientist behind the experiment is the only one who knows the key to their survival, but he has lost his memory after an accident. Racing against time, the story focuses on the two dynamic individuals' attempt to resume normalcy and catch up on the lost time of their lives.
Seo Hyun-chul as Hwang Gab-soo (46/66),[7] the professor in charge of the frozen human experiments. He was seriously hurt in a car accident that caused him to be comatosed, rendering him unable to help Dong-chan and Mi-ran to regain consciousness for the next twenty years
Lee Moo-saeng as Jo Ki-beom (45),[7] Professor Hwang's assistant
Kim Bup-rae as Lee Hyung-do / Lee Seok-do, who were both twin brothers. Seok-do was one of the test subjects of Professor Hwang's experiment, and Hyung-do, who was Seok-do's younger twin brother, wanted to murder his brother and Professor Hwang in order to take his brother's place as the next-in-line CEO of their father's company
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This drama aired on a cable channel/pay TV which normally has a relatively smaller audience compared to free-to-air TV/public broadcasters (KBS, SBS, MBC and EBS).