The MNET-produced girl group IOI are the guests on the variety show "Knowing Brothers." They were the guests for the 53^rd episode.

In the episode, each member asked a question and the "Knowing Brothers" cast will answer it. The ones who get correct answers will partner with the IOI member. First was Somi, who was partnered with Sung Cheol.

Somi's part was really funny because she does not want to partner up with him as he does not have that much screen time and is known to be the least funny cast. Sung Cheol also got Doyeon and Nayoung's questions right but he still chose Somi to be his partner.

The game continued and Sohye gets to partner with Hee Chul while Sejeong gets dumped by Sang Min because he is already partnered with Mina. Pinky is partnered with Kyung Hoon and Chungha with Ho Dong. Chaeyeon and Yeunjung also did not get to partner with anyone.

When it was Yoo Jung's turn, they started pranking their leader Nayoung. They said their fake complaints to Nayoung while Nayoung was very clueless.

Then, "Knowing Brothers" backtracked to before the filming. It showed how the members, specifically Sejeong, wanted to prank Nayoung.

They successfully ended the prank and then Nayoung burst into tears cried while she was still very confused as to what is happening. Yoo Jung cried harder than Nayoung because she felt so guilty.

The other members also cried. They explained to her that it was all made up and it was a hidden camera.

During the episode, IOI celebrated their graduation party with the cast. They had a party and a fake Jang Geun Seuk came.

The party started with a dance time. After that, they did a quiz by partners. Sejeong and Chaeyeon won after getting the last question correct.

Afterwards they did another game. One partner is going to piggyback the other while they take off the hat of the opponent by using a pillow. Sang Hoon and Yoo Jung's team was definitely at an advantage because of his height.

During the final round, Mina's team and Sejeong's team ganged up on Yoojung's team. However, Chaeyeon mistakenly removed Mina's hat. Yoojung's team ultimately won in the end.

During the ending, they did a ceremony. They give each member a diploma meaning that they have graduated from being an IOI member to going to their respective companies or existing groups for future activities.