The search for K's killer gets complicated when a series of dead bodies are found -- all with a mysterious QR code on them.

Hired by a client whose family jewels are in danger of being stolen by a nefarious thief, the detectives hurry to get to it first.

When a shaman needs help finding the scattered numbers of a winning lottery ticket, the detectives race against another team for a big reward.

The team welcomes a new intern, who leads them to a grisly case involving a divorced couple, their son, and a suspicious neighbor who lives next door.

While investigating a suicide, the detectives go to a spooky village, where mysterious things happen to young women -- and outsiders are not welcome.

The detectives split up when they're hired by three estranged brothers of a chaebol family -- all eager to find their late father's will.

The detectives have fun participating in a crime game show with a K-pop group -- until things get too real.

Eager for more information about the Flower Killer, the team attends an event, where the detectives come across an unexpected death.

Hot on the Flower Killer's trail, the detectives follow a maze of clues from his home to his secret lair, where they learn a shocking truth.

Kwang-soo is back! When a client asks the detectives to uncover which of his roommates is stealing his food, they enter a house filled with secrets.

The team splits up to take on two cases: one involving a missing professor, and the other a gory murder inside an illegal gambling den.

Investigating the disappearance of a woman's corpse from the morgue, the sleuths encounter a deadly operation with disturbing plans.

With three women claiming to be his rightful fiancée, a wealthy heir calls on the detectives to deduce which he should marry.

Following clues from a chilling message and a mysterious USB drive, the team races against time to save a hostage from being killed.

After receiving a strange letter from a dead man, the detectives look for answers in his hometown - and from his four suspicious friends.

A client in need of finding a lost boyfriend contacts the team for help, but they're not the only squad of private eyes who show up to take the case.

As the team discovers the truths behind a mysterious organization, they question whether one of their very own could be hiding a dark identity.

While enjoying their break on Jeju Island, the detectives get a shocking call from K, who says Kwang-soo is a prime murder suspect and is on the run.

Jong-min comes across a diary of a dead teen girl who was possibly murdered. To find the truth, he gathers the detectives at the school she attended.

A woman turns up dead on an island off the coast of Incheon. The detectives learn that a centuries-old legend of a vampire has haunted the islanders.

Without any cases to solve, the detectives enjoy watching a magic show rehearsal -- until the show's star magician suddenly disappears without a trace.

A man who introduces himself as K's old friend offers the detectives lavish pay and a chance to partake in a special mission -- but there's a catch.

A culprit asks specifically for the detectives to escort him to the police station. In exchange, he promises to tell them everything they want to know.

The detectives receive a text message from K that was written three months ago. It asks them to come to Incheon, where their final test awaits.

Recognized for their performance, the detectives report to Jeju Island, where their first client asks them to participate in a treasure hunt.