Girls Planet 999: The Girls Saga - Season 1

The episode opens with all 99 girls being divided into three cells, each consisting of a Korean, Chinese, and Japanese contestant. Groupings are based on a variety of characteristics common to the girls, such as type of career and personal interests. Upon the girls entering the main stage and taking their seats, the host of the competition, Yeo Jin-goo, is introduced to the girls. He is then followed by the rest of the mentors. Yeo then explains the rules of the competition. Each girl is evaluated to determine whether they should be considered to become a Planet Top 9 candidate and their initial ranking is revealed prior to each performance, based on the theme song evaluation test. 

Starting from this episode, viewers and fans (also known as Planet Guardians) may start voting for their favorite contestants on Universe. Before they can vote, there are rules they need to follow in order to make the girls' dreams come true. Viewers and fans must be verified via text messages before they can start voting on Universe. Half of the votes will come from South Korea while the other half will come from overseas. These votes will determine who will move on to the next mission and who will be eliminated.

The Planet Top 9 evaluations continue, and the eventual Planet Top 9 for the episode are announced. The girls will then proceed onto the first mission.

The current cell rankings are displayed at the beginning of the episode. The contestants begin preparing for their first mission by determining their positions in the performance.

Several days before the team performances, a dance battle is held to determine the order in which the teams will perform. Following the dance competition, the teams continue to practice, with the mentors offering feedback on how to improve.

The group performances then begin.

The group performances continue. After the completion of the performances, the winning team that will get to perform on M Countdown is revealed.

During the end credits, it is revealed that only 54 contestants will survive in the following episode, meaning that 45 contestants will be eliminated.

The first ranking announcement begins. The top 16 cells are first announced.

During occasional breaks in between announcements, other activities that the girls did together leading up to the day of the announcement were shown.

The results of the Planet Pass is announced; the Planet Pass is a vote between the mentors in which one eliminated contestant from each of the 3 racial groups will be saved to remain in the competition. Following this, the new Planet Top 9 are then announced. 

Following the ranking announcement, the eliminated girls bid their farewell to the surviving contestants and leave their dormitories.

The episode begins with the 54 girls entering a room. Host Yeo Jin-goo then enters the room, explaining that the next mission would be the Combination Mission. Yeo also reveals that cells will be disbanded and cell votes will be phased out, meaning that rankings are all now individual.

He then moves on to explain the Combination Mission, stating that the 54 girls will be split into either 3-member, 6-member or 9-member teams for the mission. There are a total of 6 songs for 3-member teams, 3 songs for 6-member teams and 2 songs for 9-member teams. To determine their teams, the girls enter doors labeled "3", "6" and "9" which will lead to respective 3-member, 6-member and 9-member team songs where they will have to pick which song they want to perform.

After forming their teams, the girls then proceed to prepare for their group performances. The girls are first evaluated by the mentors through an interim check before the actual performance. The performances begin.

The four songs created for the next mission, dubbed as the "Creation Mission" is also revealed. Viewers were told to vote who they wanted to perform which song through Universe.

The Combination Mission group performances continue. After all of the performances finish performing, the winners of the Combination Mission are announced. 

During the previews for the next episode, the girls are introduced to the Creation Mission songs which were previously shown to the audience in the previous episode. 27 girls will be eliminated next episode. The planet pass will still be implemented next elimination.

The episode begins with the 54 girls being split into four different groups for the four Creation Mission songs, having been arranged through the voting of viewers. In each song, the girls are split into two proxy teams, resulting in two contestants being assigned as the killing parts of the song for their respective team. The girls begin trying out for the various positions in the song.

In the midst of preparing, the second elimination round results are announced to the girls. The top 7 contestants in each group was announced, followed by the 8th-ranking contestant of each group. Following this, the new Planet Top 9 is announced. Once the Top 9 had been announced, the Planet Pass recipients were announced. 

The Creation Mission continues with the 26 girls rearranging parts and changing lineups for their Creation Mission songs. After changing lineups and rearranging parts for their Creation Mission songs, all teams continue practicing until when they leave their dorms for a special mission called the Planet Teamwork Mission.

In the Planet Teamwork Mission, all teams must perform their Creation Mission songs no matter where they go using teamwork. Teams go to different locations to finish various missions and relax.After that all teams return to their dorms in the night and sleep in their bedrooms.

6 days after the Planet Teamwork Mission, all teams start rehearsing for their songs, but the rehearsal was interrupted when the second interim results were announced to the girls. The top 18 contestants were announced in ascending order, followed by the temporary Planet Top 9. 

After the second interim results, a scene from a month earlier showed 54 girls from the Combination Mission return for field day. On field day, the 54 girls from each group form a team and compete in a series of games. The winning team receives fleece jackets while the runner-up team receives cosmetics sets. 

The episode begins with the girls attending a fan meeting with some viewers of the show. They perform several of their past performances from the Planet Demo Stage and the previous two missions. After the fan meeting, the girls give presents to the audience.

The episode then begins to the commencement of the Creation Mission performances. After the performances, the winner is announced. Then, it is revealed that the real final mission is named the O.O.O Mission which will take place during the finale episode. Further details are revealed; the girls will be first organized into 3 different groups that will perform a debut group version of the show's theme song, "O.O.O (Over&Over&Over)". The teams were voted for by the viewers through Universe.

The episode begins with the O.O.O Mission. The girls are grouped into three different teams; two containing nine members and third containing eight. The girls arrange their parts and practice their performance. After practice, they perform their performances to the mentors. In between performances, the girls are shown video messages and performances by viewers of the show from around the world.

The winners of the O.O.O Mission were determined by the viewers of the show; the contestant of each team that accumulated the most number of YouTube likes on their respective video within 24 hours would obtain a benefit of 90,000 (nine-member) or 80,000 points (eight-member). The winners of the O.O.O mission are revealed.

The episode then proceeds to the third ranking elimination. After the seventeen survivors are announced, the Planet Pass recipient is then revealed.

The episode ends with the preview of the final episode's mission.

The episode begins with the 18 finalists performing the show's theme song. Due to COVID-19 safety measures, the only live audience was the mentors along with some of the eliminated contestants who were still in Korea at the time. There was also a live Zoom audience who was occasionally shown.

After the theme song performance, the show's host announces the opening of the final voting round, in which all live votes will be doubled. Following this, the audition and highlights videos of the 18 girls are shown. Voiceovers by the girls during the videos also explain why they are pursuing such a career, expressing their desire to debut. Host then explains the live voting process, stating that the final votes will include the first round votes from the week added with the final second round live votes. A segment then takes place where host interacts with members from the live Zoom audience. He then introduces the mentors as well as the live audience consisting of some eliminated contestants. The current 9th place candidates are then announced.

The episode then cuts to a few weeks before the finale; the 18 girls are introduced to the Completion Mission song "Shine". They learn that two teams of nine will be formed, with both teams performing the same song. The lowest ranking contestant goes first to pick which team they want to join, followed by the rest of the contestants in ascending rank order. The girls then settle their parts and prepare for the finale. Host then announces the debuting girl group's name. Afterwards, the 18 girls then perform "Shine".

After the performance, the episode cuts to a week prior where the girls watch their audition videos. They also watch videos aimed to their future selves that they filmed when the show began, as well as similar videos filmed by some of the eliminated contestants. The girls then perform "Another Dream", a pop ballad song. 

The episode then cuts to the days leading up to the finale. The girls are treated to a party where they reviewed artworks they created for one another as well as receive a lavish dinner. Afterwards, they also view polaroids that serve as memories of their time participating in the show. They then settle in front of a projector and watch video messages by some of their parents.

Host then begins to announce the debut lineup of the group. The episode comes to a close with the debuting and eliminated girls coming together, congratulating each other and exchanging hugs.