A drug squad attempts to take down a criminal organization and they must go undercover to do so, so they begin working at a chicken restaurant, that becomes famous for its delicious chicken. Due to the unexpected popularity, the detectives find themselves in a situation they never expected.

The movie depicts the three months before Choong-nyung (the future Sejong the Great) becomes king. The Annals of the Joseon Dynasty, which follows the history of the Joseon Dynasty between 1413 and 1865, leaves out records of this crucial period. While future generations would come to know him as King Sejong, the legendary figure who created the Korean alphabet and advanced the country’s scientific research and law, Prince Choong-nyung was originally dismissed as a reclusive bookworm. When his older brothers Yangnyeong and Hyoryeong fail to impress their father King Taejong, the king makes a royal command for Choong-nyung to become the next ruler of the kingdom instead.

Gurus in the late Goryeo dynasty try to obtain a fabled, holy sword, and humans in 2022 hunt down an alien prisoner that is locked in a human's body. The two parties cross paths when a time-traveling portal opens up.

While desperately searching for his missing daughter, Hae-kwan comes across an AI satellite robot that remembers sounds from all over the world. Rejuvenated by the robot's abilities, Hae-kwan begins to track down his daughter's voice. As they continue their journey, they form an unforgettable bond.