In a prologue, the cast is introduced to the settings and suspects of a murder case for the new episode. The cast then chooses their role in the episode, as a particular suspect or the detective. Other than the detective, each person is given detailed information about the suspect they are portraying including their personalities, alibi, relationship to the victim and other suspects, history, criminal motive, etc. Every suspect can conceal information until explicitly questioned by other suspects or the detective, but only the criminal can lie.
Alibi: Each player introduces themselves as the suspect they are portraying, gives some background information about their relationship with the victim, and describes their whereabouts before, during and after the crime.
On-Site Investigation: The players are separated into two teams, and given ten minutes to investigate the crime scene for clues. Each player is given a camera, and is allowed to take a maximum of ten pictures.
Briefing: All players present the evidence they have collected, and are allowed to ask other players questions concerning evidence. Each player voices out who they currently think is the criminal after their briefing.
First Criminal Vote: The detective is allowed to make a vote on who he/she suspects after hearing each player's briefing. The vote is made publicly to all of the players.
Additional On-Site Investigation: All the players gather at the crime scene for additional investigation and discussion. This segment is run at the same time as the 1-on-1 Interrogation.
1-on-1 Interrogation: The detective who is always innocent can summon the other players into the interrogation room for further questionings.
Final Criminal Vote: After all of the players have been interrogated, the game proceeds to the final vote. All players makes their final statement and debriefing of the case would be conducted by the Detective. 5 minutes of individual investigations would be permitted before each player secretly votes for who they think is the final criminal. The player who receives the most votes is arrested and locked in a makeshift prison. If the person is indeed the criminal, the detective receives two gold bars, and the innocent players receive one each. If the arrested person is not the criminal, the true culprit gets all the gold bars.
In the second season, minor changes were made to the format of the show. The gold bars are given to the cast members beforehand. If they vote correctly, they can keep the gold bar. If not, they will have to return it.
The detective is no longer allowed to make his first vote publicly, so that the cast will not be influenced. At the end of the game, if the right suspect is voted as the criminal, only those who voted correctly get to keep their gold bars. If the detective voted correctly both times, he or she gets two gold bars. If the suspect successfully hides his or her identity, he or she gets all six gold bars.
In episode 12, all six cast members are suspects.
In the third season, all the scenes have become realistic, in which the cast members experience the whole crime setting themselves. Props and the background of the cases are all original and solid, such as the hotel in episode one.
There are one to two victims for each case, making the cases far more complex than the previous two seasons.
Season 4 began in October 2018, and continued to use actual sets for some of the episodes. The detective's assistant role, which appeared briefly in Season 2, was brought back for this season and played by various university students.
Gathering of the Famous Detectives (IQ test) Victim: Evil Manager, Zhen Badao He Jiong: 90 points Sa Beining: 88 points Gui Gui: 50 points Qiao Zhenyu: 45 points Wang Ou: 30 points
He Jiong is the smartest detective.
3 April 2016
Fall of the Campus Beauty Victim: University M, student Xia Qingtian Detective: Sa Beining Boyfriend: He Jiong Club Member 1: Wang Ou Club Member 2: Qiao Zhenyu Club Member 3: Gui Gui Club Teacher: Bai Jingting
Unable to Triumph in the Skies Victim: MG carrier airline, co-pilot Zhen Detective: Sa Beining Pilot: Da Zhangwei Flight Attendant 1: Bai Jingting Flight Attendant 2: Wang Ou Head Stewardess: Gui Gui Trainee: He Jiong
Battle within the 'fresh meat' boy group (No Zuo No Die / NZND) Victim: MG entertainment group, Manager Zhen Detective: Gui Gui Main Vocalist: Da Zhangwei Vocalist: Sa Beining Visual: He Jiong Rapper: Bai Jingting Dancer: Chen Ruoxuan
Reply 1998 Victim: Gaming Room, Boss Zhen Detective: He Jiong Step-daughter: Gui Gui Worker: Sa Beining Town Beauty: Wang Ou Town Beauty's Son:Bai Jingting Town Resident: Kevin Tsai
22 May 2016
All Because of Beauty Victim: Very Pretty Plastic Surgery Hospital, Surgeon Zhen Detective: Bai Jingting Nurse: Gui Gui Cleaner: Wang Ou Patient: Sa Beining Deputy Director:He Jiong Investor: Zhang Ruoyun
29 May 2016
Decisive Battle of the UEFA Champions League Victim: Football Club, Main Striker Zhen Detective: Sa Beining Player: Bai Jingting Cheerleader: Wang Ou Team physician: Gui Gui Retired player:He Jiong Player on opposing team: Qiao Zhenyu
Avengers' Broken Alliance Victim:The Avengers: Rise of the Barbeque Hero film set, Warrior Zhen Detective: Gui Gui Beauty: Wang Ou Bungee Jumping Actor: Sa Beining BBQ Grill Actor: He Jiong Facial Mask Actor:Da Zhangwei Best Actor: Jackson Wang
Ghost in the General's Residence Victim: Ming Country, M City, Warlord Zhen Detective: He Jiong Chief of Staff: Sa Beining Sixth Concubine: Wang Ou Ghost Hunter: Da Zhangwei Family Tutor: Gui Gui General's son: Aaron Yan
19 June 2016
Wheel of Fate Victim: 'Titantic' passenger liner, President James Zhen Detective/Pirate: Da Zhangwei Carl: He Jiong Jack: Sa Beining Rose: Wang Ou Captain: Bai Jingting Sorceress: Gui Gui
Nirvana in Fire: The Princess is Here Victim: Crown Prince's residence, Princess Zhen Detective: Bai Jingting Advisor: He Jiong Crown Prince: Sa Beining Concubine: Gui Gui General: Wei Daxun Palace maid Yang Rong
Midnight Train Victims: Rich Merchant Zhen, Passenger Hai Detective: He Jiong Passenger 1: Sa Beining Passenger 2: Bai Jingting Stewardess: Wang Ou Passenger 3: Ariel Lin Passenger 4: Dong Li Steward / Witness: Lin Bohong
Arrested:Sa Beining(Passenger Sa)
17 February 2017
Night at the Museum Victim: Museum Director Zhen Detective: Gui Gui Artefact Collector: He Jiong Officer: Sa Beining Young Master: Bai Jingting Mysterious Person: Wang Ou Night guard: Wei Daxun
24 February 2017
Jackson Wang, Qiao Zhenyu
See You on Friday Victim: Popular actress Zhen Detective: Jackson Wang Visual: He Jiong Vocalist: Gui Gui Rapper: Bai Jingting Entertainment reporter:Wang Ou Student: Qiao Zhenyu
3 March 2017
Jackson Wang, Qiao Zhenyu
2046 Victim:Genius Zhen, Tester Gui Detective:Wang Ou Perfect Robot: He Jiong Assistant: Sa Beining Scientist: Jackson Wang Transport Robot: Qiao Zhenyu
10 March 2017
Wei Daxun, Yang Rong
Terrifying Nursery Rhyme: Part 1 Victim: Mansion in the mountains, Duke Zhen Detective: Sa Beining Lawyer: He Jiong Postman: Bai Jingting Duchess: Gui Gui Housekeeper:Wei Daxun Noble Lady: Yang Rong
Hotel Horrors: Part 1 & 2 Victim: Richest Man Zhen Hong Detective:Sa Beining Manhua Fanatic: He Jiong Sprinter: Leo Wu Lei Best Game Player: Bai Jingting Hotel Manager: Zhang Ruoyun Vet: Sa Beining Keyun: Emma Wu
Blame for My Beauty! Part 2 Victims: Detective Da, Nurse Rong, Xiao Ting Detective:He Jiong Patient: Bai Jingting Gua sha practitioner: Pan Yueming Professional Sleeper: Wei Chen Jianbing Stall Owner: Sa Beining Canteen Cook: Emma Wu
Detectives' Society Detectives: He Jiong, Sa Beining, Wang Ou, Bai Jingting, Zhang Ruoyun, Liu Haoran
2 November 2018
Escape the Nameless Island: Part 1 Victim: Social Media Writer Zhen Xiangdi Detective:Sa Beining Serviceman: He Jiong Editor: Wang Ou Shoe Retailer: Bai Jingting Doctor: Zhang Ruoyun Leaflet distributor: Liu Haoran
9 November 2018
Zhang Ruoyun, Liu Haoran, Wei Daxun
Escape the Nameless Island: Part 2 Victim: Editor Wang Ou Detective:Sa Beining Serviceman: He Jiong Nurse: Wei Daxun Shoe Retailer: Bai Jingting Doctor: Zhang Ruoyun Leaflet distributor: Liu Haoran
He Jiong (murderer), Zhang Ruoyun (mastermind)
Mastermind won (Zhang Ruoyun)
16 November 2018
Deng Lun, Justin (黄明昊)
Mysterious Call Victim: Zhen Jia, Zhen Xiaoyu Detective:N/A Math Teacher: He Jiong Genius Mathematician: Sa Beining Tour Guide: Wang Ou Student 1: Gui Gui Student 2: Deng Lun Student 3: Justin
Fantasy Entertainment Resort Victim: Costume Actor Zhen Detective:Sa Beining Ride Manager 1: Qiao Xin Ride Manager 2: He Jiong Vampire Actor: Da Zhangwei Space Ride Manager: Gui Gui Clown: Justin
Arrested: He Jiong
11 January 2019
Liu Haoran, Zhang Ruoyun, Xie Na
Number One Player Victim: Player Zhen Detective:Liu Haoran Player 1: Xie Na Player 2: Bai Jingting Player 4: Sa Beining Player 5: He Jiong Player 6: Zhang Ruoyun
19 January 2019
Number One Player II Victim: Various characters Little Cup / Third Boyfriend / Assistant: He Jiong Little Spoon / Current Boyfriend / Cleaner: Xie Na Little Pot /Fourth Boyfriend / Receptionist: Sa Beining Little Bowl / Second Boyfriend / Boss: Bai Jingting Little Chopstick / Fifth Boyfriend: Liu Haoran Little Saucepan: Zhang Ruoyun
Bai Jingting, He Jiong, Sa Beining
Arrested: Zhang Ruoying, Liu Haoran
26 January 2019
Awards Ceremony Victim: N/A Detective:N/A Attendees: Sa Beining He Jiong Bai Jingting Zhang Ruoyun Liu Haoran Xie Na
The second episode of season 3 was pulled down 30 minutes before the show was due to be uploaded to streaming website Mango TV on September 29. The crew of Who's the Murderer responded by saying that "the show needed more time to optimise the plot".  The episodes returned online on November 3rd.