In a dystopian future devastated by air pollution, the survival of humanity depends on the Black Knights — and they’re far from your average deliverymen.

Woo Tae Kyung joins the Saebit Boys High School Council with the intentions to make friends, inadvertently meeting his first love.

Ma Dong-chan and Go Mi-ran are both frozen during an experiment. They wake up 20 years later instead of 24 hours later and must keep their body temperature above 30°C in order to survive.