Ključna riječ National Intelligence Service Nis

Kada ga pošalju u opasan grad da istraži tim specijalaca i njegova zloglasnog vođu, cijenjeni tužitelj uplete se u smrtonosni rat među špijunima.

Children who live in hiding with superpowers, along with their parents who live with painful secrets of the past, face enormous dangers together.

Stuntman Cha Dal-geon gets involved in a tragic airplane crash and ends up discovering a national corruption scandal in the process. Go Hae-ri, the oldest daughter of a deceased marine, decides to work for the National Intelligence Service as a secret ops agent in order to support her mom and younger siblings, although all she wanted to do is to become a civil servant.

Kwon Dohoon is an expert sniper and a secret agent working for the National Intelligence Service. To conceal his true identity, he lives a double life as a regular trading company employee, keeping even his wife Kang Yura in the dark. Though he is occupied with his work, Dohoon cherishes his wife deeply. Meanwhile, Yura, a dedicated homemaker, harbors a secret. Their tranquil existence is thrown into turmoil when Jo Taegoo emerges, posing a threat to their carefully crafted façade.

Han Ji-hyuk, an NIS agent gone MIA, returns after one year to join a new team as he searches for his lost past.

After his mother is brutally murdered by the Triad in Thailand, Soo-hyun is adopted by NIS agent Kang Joong-ho, and he grows up with Min-ki like brothers. Min-ki and Soo-hyun both become NIS agents later on. One fateful day, Soo-hyun meets Ji-woo after last seeing her in Thailand when he was a child. They start dating. One day, Soo-hyun ruins a mission when the suppressed memories of the day his mother died surfaces in his mind. NIS Director Jung gives Soo-hyun an undercover assignment to infiltrate the Triad and Soo-hyun takes the job. Soo-hyun fakes his death and assumes a new identity to become a member of the Triad. With his fake identity and new name, he prowls the back alleys of Bangkok.