The story unfolds when a bomb that responds to sound is discovered at the center of the city.Don't make a noise otherwise the bomb will go off. Former lieutenant commander Do yeong (Kim Rae-won) suffers from PTSD caused by the hellish submarine accident in which he lost his colleagues. Even though he is revered as a national hero, he feels guilty and tormented by his own family estrangement. One day, Do-yeong receives a cryptic phone call from a mysterious person, threatening he'll blow up a football stadium with improvised explosives triggered by a certain decibel. In the nick of time, Do-yeong saves innocent lives but the terrorist remains intent on inflicting further casualties, including Do-yeong's wife and daughter. Now he must race against the clock to track the terrorist down and save his family as well as other people. Amid this impossible task, the unforeseen consequences of a secret he left buried in the deep sea resurfaces.�Megaplus MThe story unfolds when a bomb that responds to sound is discovered at the center of the city. This terror attack occurs following an incident that happened one year ago in a submarine, and important figures such as a submarine commander, reporter, and a member of the Defense Security Support Command come together to try and stop the bomb. Kang Do Young is a Navy submarine commander. He's a key figure linked to the submarine incident that was the cause of the terror attack. Oh Dae Oh is a passionate reporter. Cha Young Han is a member of the Defense Security Support Command.