A decades-old incident involving a group of five friends who ran an illegal pro-democracy broadcasting station during the Fifth Republic in South Korea brings together three different people—an illegal "night courier" with the codename "Healer" (Ji Chang-wook) who possesses top-notch fighting skills, a reporter from a second-rate tabloid news website (Park Min-young), and a famous journalist at a major broadcast station (Yoo Ji-tae).[9][10][11] While trying to uncover the truth from that 1992 incident and a series of present day murders, they grow into honest reporters who try to blur the lines of conflict between truth and reality, even if that means fighting media honchos.
Ji Chang-wook as Seo Jung-hoo / Park Bong-soo / Healer
Park Si-jin as young Jung-hoo
Go Woo-rim as child Jung-hoo
Choi Jung-hu as toddler Jung-hoo
An illegal "night courier" who works under the alias "Healer". Renowned for being the best in his field, Jung-hoo is equipped not only with advanced technology and a trusty hacker sidekick, but also his superb fighting skills. He will perform any task except anything involving murder. His ultimate goal is to save money and buy an uninhabited island off the coast of Panama and to live there alone, but that changes after being given an order by his client, Kim Mun-ho, to find and protect a girl named Young-shin from the people who want her dead but he later falls in love with Young-shin.
A strong-willed and quirky internet news reporter who dreams of becoming a legendary reporter. However, her dreams are put to the test when she finds out about her hidden past as the lost child Oh Ji-an. Due to her abusive past, Young-shin is traumatized and suffers from panic attacks whenever she sees violence. She later falls in love with her protector, Jung-hoo.
A star reporter, and brother to Kim Moon-sik, the CEO of a large news company. His goal is to last each day and to find Oh Ji-an, a supposedly dead child whom he suspects to still be alive. He pays Jung-hoo (as "Healer") to find and protect Ji-an (now known as Young-shin) from the people that want her dead, out of guilt for not fully investigating the truth about a 1992 incident that ended in the tragic deaths of two out of five best friends, and the crippling of a third.
Kim Mi-kyung as Jo Min-ja, Hacker Ahjumma, a former detective specializing in cyber crimes.
Oh Kwang-rok as Ki Young-jae, Jung-hoo's teacher (and the first "Healer"), one of five friends from the past.
Choi Dong-gu as young Young-jae, Motorcycle rider and distractor during the illegal radio broadcasts.
Taemi as Kang Dae-yong, "Healer's" assistant.
Ji Il-joo as Seo Joon-seok, Jung-hoo's father, an engineer of the illegal radio station and later a photographer working with Oh Gil-han.
Lee Kyung-shim as Jung-hoo's mother
Song Ji-in as young Jung-hoo's mother
Park Sang-myun as Chae Chi-soo, Young-shin's adoptive father, a lawyer specializing in defending clients accused of burglary who also runs a café where he has employed many of his former clients.
Woo Hyun as Chul-min, a former convict and one of Chae Chi-soo's clients who now works at the café.
Park Won-sang as Jang Byung-se, head of "Someday News", an internet tabloid news site where Chae Young-shin works.
Choi Seung-kyung as Yeo Gi-ja, "Reporter Yeo" at "Someday News".
Park Sang-won as Kim Moon-sik, one of the initial five friends, now a highly successful CEO of a news agency.
Son Seung-won as young Moon-sik, driver of the truck from which the five friends ran their illegal radio station.
Do Ji-won as Choi Myung-hee, Young-shin's biological mother, living in the present with Kim Moon-sik and using a wheelchair.
Jung Hye-in as young Myung-hee, one of the lead reporters in the illegal radio station.
Woo Hee-jin as Kang Min-jae, news director at "ABS News", where Kim Moon-ho works at the start of the story and also his love interest.
Jang Sung-beom as Lee Jong-soo, Kim Moon-ho's assistant.
Park Sang-wook as Bae Sang-soo, head of a rival "night courier" agency.
Hong Seung-jin as Yo-yo, employed by Bae Sang-soo.
Jo Han-chul as Yoon Dong-won, a detective specializing in cyber crimes, formerly Jo Min-ja's hoobae.
Oh Jong-hyuk as Oh Gil-han, Young-shin's biological father, one of the lead reporters in the illegal radio station and a regular reporter after the fall of the Fifth Republic.
Jung Gyu-soo as Oh Tae-won, Moon-sik's secretary and agent of "The Elder".
Kim Ri-na as Joo Yeon-hee, an actress who turns to Chae Young-shin and her father for help.
Choi Jong-won as Park Jung-dae, "The Elder", a shadowy figure operating behind the scenes and the CEO of Omega Holdings formerly known as Omega Venture Capital.