Round 4 begins and unlike previous missions, they must prepare two performances; one for vocals and one for dance. If they don't get enough &BALLs in this round, the trainees will not be able advance to the final round. The trainees go through practice, interim evaluations and after performing, they discover whether they can completely fill the &RING. At the end, they find out how many members will be in the final lineup. There is an announcement about how the debut group will be decided and a surprise final episode is to be aired live while voting begins.

The trainees find out about the progress of the &RING and the mission for Round 4: the BTS mission and look over the songs at their dorm, which is shown for the first time. Days later, a surprise mission is announced and only the winning team will receive a benefit. Tomorrow X Together visits and the trainees have a meal together and chat. After the interim check, everyone hears a shocking announcement about the &BALLs they will receive. On the day of performances, BTS sends a special message.

Round 3 shows the trainee teams as they make their through an interim check at a special venue, rehearsals and a final performance, set on a stage that is larger than they anticipated. The trainees are tasked with completing the 'Seventeen Legendary Mission', covering three songs which they must also self-choreograph. In contrast to other rounds, the 15 trainees learn that the number of &BALLS they receive will be announced live after each performance in the presence of the producers and other trainees.

After the mission for Round 3 is revealed, the 15 trainees get together in their teams to practice. They must pick a leader and choose a team name. The groups work together through practice and interim checks while getting closer. SEVENTEEN delivers a special mission to the trainees where there will be a "variety contest" to give them a chance to earn additional &BALLS. The trainees go outdoors to a lodge where they open up to each other and talk about what has been on their minds. They also receive surprise special messages from afar.

Team Nicholas re-charge at an ocean-side grilled eel restaurant while K's team visit a night market in Busan and try various street food. Team K meets a hurdle as a member is unable to participate and they must re-practice with new formations and positions days before the final performance. Nicholas' team show a powerful performance, while Taki's team challenge a performance involving modern dance. Seventeen makes an appearance to reveal the trainees' third mission.

The second mission is the "Concept Mission". The songs are revealed and the trainees are divided into different teams, each group being led by one debut trainee. EJ's team receives a disappointing feedback in the interim check; they also travel to Busan and go to a seiro-mushi restaurant before their performance to spend time off and discuss ways to improve.

&Audition – The Howling is first introduced by Bang Shi-hyuk as a project in which debut trainees K, Nicholas, EJ and Taki will be joined by newly selected members to debut as Hybe Labels Japan's first boy group. The show begins with the four meeting Enhypen and then the other 11 trainees. All are then presented with their first task, the "Signal Song Mission". The meanings of &BALL and &RING are revealed and the episode documents the trials and hardships the trainees face while practicing for their first performance as a group.