In the show, YG Entertainment founder and producer Yang Hyun-suk traveled to music agencies across Korea to find up-and-coming K-pop stars.

[6] Mix Nine was a collaboration project between director Han Dong-chul, producer Yang Hyun-suk, and JTBC.

[10] 170 trainees were chosen by Yang Hyun-suk and guest judges CL, Zion.T, Seungri, and Taeyang.

[18] On September 18, a 2-minute video teaser was uploaded via YG Entertainment's YouTube in which Yang briefly described the show concept.

[19][20] Through his Instagram account, Yang also constantly updated which companies he already visited and how many trainees had passed so far.

[8][21] At the same time, the show also released photos of trainees who had undergone the audition, which included members from KNK, 24K, ONF, Loona, A.C.E and JJCC.

[25] About a month after, JTBC released a representative image of the show on October 11 with the caption 'Save a Shining Boy and Girl' and the logo 9.

The trainees' auditions are simultaneously watched by the judges, their agency's CEO, and their co-trainees in the bus.

Towards the end of the episode, BigBang member Seungri joins Yang in his car going to one of the biggest agencies in South Korea, JYP Entertainment.

[38] Again, the show starts with the participants gathering in a room to do the '1-Day Special Mission'; a new set of "Debut Team" will be formed after their evaluation.

[37] Participants are given two (girls) or three (boys) dance songs for them to perform in front of judges Yang Hyun-suk and Lee Seungri.

Participants who are given the pass by the judges would proceed to the singing portion and only nine people would be chosen to be included in the "Debut Team".

All contestants are divided into four levels: Top 9, A, B, and C. At that moment, the 'Mix Nine's VLive Showcase' is announced along with the show's theme song, "Just Dance", and its choreography.

Right after, their mentors tell them their new mission: record their song and dance individually from 9AM to 3PM for re-evaluation of their level, or they are automatically put to C-class.

A new set of Debut Team are formed at the end: ONF's Hyojin and Fave's Lee Sujin are chosen by Yang as the male and female centers, respectively, for their first live performance.

The trainees are tasked to perform live in groups based on positions they want to debut in: vocal, dance or rap.

Yang announces whether each member passes or gets eliminated in the show based on the showcase, position battles, additional points and online votes.

Also, the songs, remastered by YG producers, are decided through the survey about the contestants' role models and life-song.

Both male and female teams will be given three songs - Kang Wook-jin, Diggy, and LIØN's "Hand in Hand"; FUTURE BOUNCE's "Super Freak"; MC Mong's "Stand By Me"; and "After This Night"; Ilhoon and Kamen Rider's "Hush"; and Kim Dohoon's "Dangerous Girl".

[54][55] Participants who survived are re-grouped (a maximum of nine members each) due to uneven distribution after the last elimination round.

[58] By the end of the episode, a preview of the Debut Team going to BigBang's concert as a present by Yang Hyun-suk was shown.

Shin Ryu-jin retains her 1st rank while Kim Hyo-jin replaces Woo Jin-young for the first time.

After finalizing the teams of four groups at the end of the episode, 12 participant representatives' audition presentations or live performances are shown according to their positions: dance, rap, vocal.

Both Noh Hong-chul and Jang Sungkyu host the show while the final judges include Seungri, Taeyang, Zion.T and Yang Hyun-suk.

[65][66] On June 26, 2018, Happyface Entertainment, whose male trainee Woo Jin Young was set to debut as their center, filed a lawsuit against YG for 10 million Korean won (over 8,800 USD).

[67] “More than to be compensated for all the damages we have received, this is a symbolic amount filed in our hopes that Korean popular culture, the home of hallyu, will progress healthily without the overuse of power by large companies," stated a source from Happyface.