Nobody Knows

Composer

• 
  Park Se Jun

Director

• 
  Lee Jung Heum

Music Editor

• 
  Park Se Joon

Screenwriter

• 
  Kim Eun Hyang

Main Role

• 
  Kim Seo Hyung

  Cha Young Jin

  Main Role
• 
  Ryu Deok Hwan

  Lee Sun Woo

  Main Role
• 
  Park Hoon

  Baek Sang Ho

  Main Role
• 
  Ahn Ji Ho

  Go Eun Ho

  Main Role

Support Role

• 
  Min Jin Woong

  Lee Jae Hong [Seoul police department / Detective]

  Support Role
• 
  Kang Seo Ha

  Yun Ja Yeong [Seoul police department]

  Support Role
• 
  Jang Young Nam

  Jung So Yun [Eun Ho’s mother]

  Support Role
• 
  Yoon Chan Young

  Ju Dong Myeong [Shinsung Middle School]

  Support Role
• 
  Kwon Hae Hyo

  Jang Gi Ho [New Life Church]

  Support Role
• 
  Shin Jae Hwi

  Oh Du Suk [Manager of Millennium Hotel]

  Support Role
• 
  Tae Won Seok

  Ko Hee Dong [Head Security of Millennium Hotel]

  Support Role
• 
  Park Min Jung

  Bae Sun Ah [Manager of Millennium Hotel]

  Support Role
• 
  Moon Sung Keun

  Hwang In Bum [Seoul police department]

  Support Role
• 
  Jo Han Chul

  Yun Hui Seop [Chairman of Shinsung Middle School]

  Support Role
• 
  Yoon Jae Yong

  Ha Min Sung [Shinsung Middle School]

  Support Role
• 
  Seo Young Joo

  Kim Tae Hyung [Eun Ho's caretaker]

  Support Role
• 
  Jeon Seok Chan

  Kim Byung Hee [Seoul police department / Detective]

  Support Role
• 
  Baek Soo Jang

  Park Jin Su [Seoul police department / Detective]

  Support Role
• 
  Park Chul Min

  Han Geun Man [Seoul police department / Chief Detective]

  Support Role
• 
  Lee Chae Eun

  Hong Eun Joo [Seoul police department]

  Support Role
• 
  Yoo Soon Woong

  Yoo Pan Sool [Church staff]

  Support Role
• 
  Kang Shin Il

  Seo Sang Won [Pastor]

  Support Role
• 
  Baek Hyeon Ju

  Im Hee Jung [Stigmata's victim]

  Support Role
• 
  Ahn Mi Na

  Lee Sun Kyung [Sun Woo's older sister]

  Support Role
• 
  Ok Ye Rin

  Yoon Ji Won [Hee Sub & Sun Kyung's daughter]

  Support Role
• 
  Lee Joo Young

  [Ha Min Sung's mother]

  Support Role
• 
  Han Soo Hyun

  Kim Chang Soo [So Yun's boyfriend]

  Support Role

Guest Role

• 
  Kim Sae Ron

  Cha Young Jin [Young] (Ep.1-3, 13)

  Guest Role
• 
  Kim Si Eun

  Choi Soo Jung [Young Jin's best friend] (Ep.1-2, 13)

  Guest Role
• 
  Lee Seung Yeon

  [Joo Han Sol's aunt] (Ep.5)

  Guest Role
• 
  Jang Jae Ho

  Choi Dae Hoon [Ha Min Sung's chauffeur] (Ep.1-3, 6, 8)

  Guest Role
• 
  Min Sung Wook

  Kevin Jung [CEO] (Ep.6-7)

  Guest Role
• 
  Jo Sun Mook

  [Secretary General of New Life Church] (Ep.1-2, 5, 7)

  Guest Role
• 
  Jeon Moo Song

  Kwon Jae Cheon (Ep.12, 15)

  Guest Role
• 
  Seo Yi Sook

  [Soo Jung's mother] (Ep.1,2,16)

  Guest Role
• 
  Kim Joon Eui

  Go Eun Ho [Young] (Ep.1-2)

  Guest Role
• 
  Kim Nak Gyun

  [Detective]

  Guest Role
• 
  Park Jung Eon

  [Pediatric ward mother](Ep.9)

  Guest Role
• 
  Im Jae Geun

  [Forensic Scientist] (Ep.4)

  Guest Role
• 
  Kim Dong Kyu

  [Forensic Scientist]

  Guest Role
• 
  Ham Sung Min

  [Young Shik's friend] (Ep. 6)

  Guest Role
• 
  Jang Eui Don

  Choi Man Gi [Detective] (Ep. 4)

  Guest Role
• 
  Ryu Sung Rok

  Lee Young Shik (Ep.6)

  Guest Role
• 
  Jung Ji Hoon

  Baek Sang Ho [Child] (Ep.6, 11-12)

  Guest Role
• 
  Baek Jae Woo

  Baek Sang Ho [Young] (Ep.13, 15)

  Guest Role
• 
  Seo Kwang Jae

  [Orphanage Director] (Ep.13)

  Guest Role
• 
  Park Jin Yeong

  Kang In Jik (Ep. 13-14)

  Guest Role
• 
  Shin Mi Young

  [Pan Sul's neighbor] (Ep. 14)

  Guest Role
• 
  Jung Seung Kil

  [Principle of Shinsung Middle School] (Ep.3, 9)

  Guest Role
• 
  Choi Go

  Joo Han Sol (Ep.5-6, 9, 11)

  Guest Role
• 
  Sung Hyun Mi

  [Restaurant owner] (Ep. 10)

  Guest Role
• 
  Seo Joon Hyung

  Jae Min (Ep. 7)

  Guest Role
• 
  Bae Ho Geun Guest Role
• 
  Sung Min Jun

  Lee Sun Woo (Child) (ep.5)

  Guest Role
• 
  Shin Hee Chul

  [Policeman]

  Guest Role
• 
  Choi Ji Yeon

  [Disciplinary hearing member] (Ep.13)

  Guest Role
• 
  Lee Seung Jin

  [Paramedic]

  Guest Role
• 
  Kim Woo Jin

  [Hotel employee] (Ep. 10)

  Guest Role
• 
  Lee Gun Ha

  Yoo Hee Seob [Young]

  Guest Role
• 
  Ha Min

  [Jae Min's mother] (Ep. 1)

  Guest Role
• 
  Park Se Hoon Guest Role
• 
  Choi Gyo Shik

  [Motorcycle shop worker] (Ep. 15)

  Guest Role
• 
  Kim Min Kyung

  [first victim's mother ](ep.1)

  Guest Role
• 
  Jung Soo Bum

  [Classmate]

  Guest Role
• 
  Lee A Ra

  Lee Seon Kyeong [Young]

  Guest Role
• 
  Nam Yun Seo

  Bae Seon Ah

  Guest Role
• 
  Park Shi Yoon

  Oh Doo Seok [Young]

  Guest Role
• 
  Kwak Jin

  [Chief of school affairs]

  Guest Role

Bit part

• 
  Hwang Hyun Jeong Bit part
• 
  Joo Seung Min

  [Teacher]

  Bit part
• 
  Lee So Yi Bit part

Unknown

• 
  Han Ji Won Unknown