In 1999, Dong-chan secretly plans a "Frozen Human" project. He freezes himself with Mi-ran.

Dr. Hwang, the only person who can defrost Dong-chan, is missing. Then, 20 years have passed.

Dong-chan and Mi-ran are finally defrosted in 20 years. Then, they go back to where they were.

Mi-ran seeks compensation; Byung-shim's heart races after 20 years apart.

Everything is confusing, and Mi-ran starts an internship. Then, Dong-chan and Mi-ran are kidnapped.

Dong-chan reveals he has participated in a cryogenics experiment to save Mi-ran. Everyone panics.

Mi-ran and Dong-chan get lost. The weather is getting hot, and they are getting hotter.

After the kiss, Mi-ran and Dong-chan become awkward, and Mi-ran apologizes for kissing him.

Mi-ran is confused by how Dong-chan behaves. Ha-young warns Mi-ran not to put Dong-chan in trouble.

After hearing that they can't have normal life from Dr. Hwang, Dong-chan runs to Mi-ran.

Knowing everything, Ha-young visits Hyeong-du and tells him that what she wants is Dong-chan.

Dr. Hwang is kidnapped. Mi-ran and Dong-chan suffer side effects from the experiment.

Dong-chan moves into Mi-ran's house. When they become close, he discovers Ha-young's secret.

Ha-young saves Mi-ran from an intended accident. But, Mi-ran is startled to know Ha-young's secret.

Terry Kim is still missing. Dong-chan does a test to restore his body temperature.

Mi-ran is back in the capsule, and everyone is in despair. Dong-chan waits for her to wake up.