The story unfolds when a bomb that responds to sound is discovered at the center of the city.

In a mythical land called Arth, the inhabitants of the ancient city of Arthdal and its surrounding regions vie for power as they build a new society.

A high-school teacher in 1983 and a detective in 2015 join forces through their dreams to change the perilous fate of the woman they both love--30 years apart.