Since the case “Jack The Ripper" that shocked everyone in Seoul Korea which happen about 10 years ago had ended with failure so far, the police is deploying to continue this case from now on. To continue to investigate the case which placed for 10 years, they liberal a brand new criminal police combination. With the superior look and remarkable strength of these new polices, they will be soon facing the other legal case and not only their case. Besides that, calm and silent criminal police woman and the new criminal police man of the ex-FBI, how will the spark between them be happen? Will the new criminal police group make their own work successfully?

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 Lee Jongsuk

New criminal police of the ex-FBI. 22 years old. He had being FBI at America from 20 years old within 2 years. He then meet with the others new criminal polices when he starts back to Korea. He always feel interesting with his new colleague --- Kwon Yuri.

Kwon Yuri

Not a new criminal police as she had being a police since she was out of college at the Seoul police station. 20 years old. She is famous and be amazing person in all of the polices in Korea for doing any mission as her small age. She always keep calm and be silent in the group.

Im Yoona

One of Yuri's friend in the group. 20 years old. She is very worship at Yuri's amazing work. Complete the mission smartly with her partner and also her boyfriend--- Lee Seunggi.

Lee Seunggi

Yoona's boyfriend. 22 years old. Smart and intelligent in doing every work. Always stay sweet with Yoona. Interesting with Donghae that had being a FBI.

Kim Taeyeon 

Leader of the group. 21 years old. She is also as famous as Yuri in all the polices of the world as she did this job with Yuri at the same time. She plays the role of Yuri's sister as she is her best friend since they are small. She knows all Yuri's secret.

Baekhyun

He likes Taeyeon. 23 years old. He always skip the mission and didn't act serious at work to make Taeyeon keep looking at him but his plan just make Taeyeon dislike him the most.

Tiffany Hwang (Hwang Miyoung)

Close with Taeyeon since she gets in the group. 21 years old. She will be a little silly and careless when get into work. Get her work with her partner and also her boyfriend---- Nickhun.

Nickhun

Baekhyun's friend. 22 years old. Tiffany's boyfriend too. He always help Tiffany when she gets into the trouble of their work. He is the best helper in the group.

-The others member maybe will be appear in the story shortly.