B1A4 are introduced as the fathers this season, but in order for them to meet the children, they have to pass a 'Daddy Qualification Test,' which includes breaking tiles and answering questions. The first two that are able to pass the qualification test get to have a special lunch date with the children, while the other three go back to the dorm to prepare for the children's arrival. At the dorm, after the children arrive, B1A4 is split into groups to prepare dinner, having to tumble to earn money. During the meal, B1A4 is faced with difficulty in trying to have Eunsol open up to them as she won't eat what they have prepared. The end of the episode also starts the 'Ring the Golden Bell with B1A4' corner with guest MC Jang Dong-hyeok.

B1A4 continue their 'Ring the Golden Bell with B1A4' corner with guest MC Jang Dong-hyeok, a corner to test B1A4's knowledge about the city of Seoul. At the end of the corner, the two members with the highest score get to go on a luxury Seoul outing with the two children, while the three remaining members get a punishment. Later, the three members move things and get ready in the baby house for the children's arrival. Once again B1A4 tumbles to earn money for dinner, keeping the extra money with Baro, who they name their treasurer. Eunsol also has difficulty again in opening up to B1A4 during their dinnertime.

B1A4 attempts to become close with Eunsol through one-on-one time with her, with the exception of Gongchan who is not present because of his kidney removal surgery, he comes back in the next episode. Before the children's arrival, the four remaining members of B1A4 set out to buy something to help close the distance between them and Eunsol. One by one the members have their one-on-one time in a separate room with Eunsol, but are being watched by the rest of the members and by a child psychologist in another room, who also had one-on-one time with Eunsol before. Once every member has gone, the child psychologist gives her thoughts on what B1A4 could do to help them become close with Eunsol. In the end, the two members who are ranked the highest make rice cakes with the children and the two members that are ranked the lowest volunteer at a kindergarten to help them understand children more. The end of the episode also starts the second part of 'Ring the Golden Bell with B1A4.'

'Ring the Golden Bell with B1A4 part 2' continues. At the end of the quiz, the winner becomes King for the next segment, which is B1A4 learning English. B1A4 attend an English lesson with a native English speaker in hopes of teaching their children English. Later at the baby house, while B1A4 is teaching the children English, Lauren from MBLAQ's Hello Baby, makes a surprise appearance.

In order to enhance their physical strength, the B1A4 members are split into two teams with the children in order to have their own Olympics. After each round, the winning team gets the prize that is offered for that particular round. After that, B1A4 have an apple pealing contest to see who becomes the mother of the group before they head off to an etiquette center with the children in hopes of teaching them right from wrong. Upon finishing the etiquette class, the members and the children split up into two groups, with the chosen mother as the MC, to test themselves on what they learned during the day, the winner getting snacks.

B1A4 and Eunsol head for a trip to the countryside to visit Hyunwoo at his grandmother's house. There they play in the valley and some of the members even go off and pick and steam their own corn to sell. With the money earned from selling, the members are able to buy the utensils that they need for dinner that night. However, in order to get the ingredients for their dinner, they have to enter an abandoned school one by one at night.

The members continue entering the abandoned school one by one to obtain the ingredients for their dinner. The next day, the members and the children help out Hyunwoo's grandmother in the field picking chilies until it starts to rain. The members then hold their own fashion show with the outfits they are wearing for the fieldwork with Hyunwoo's grandmother and her friends choosing the winner. Immediately after the fashion show, though, Baro gets taken to catch a chicken for lunch and the rest of the members are left to care for the babies. That night, B1A4 creates a music video for 'Baby Goodnight' with the rest of the villagers. At the end of the episode, the children surprise B1A4 at their Hat's On Fansign.

With special guest MC Jang Dong-hyeok, B1A4 set out to teach the children the basic rules to follow, such as knowing when to cross the street, knowing to not eat things that fall on the ground, and not to follow strangers. Through each of the simulations, B1A4 teaches Hyunwoo and Eunsol what they should and should not do. Later B1A4 and Jang Dong-hyeok go to a kid's cafe and let Baro and Eunsol have alone time and Jinyoung and Hyunwoo have alone time since the pairs are still awkward with one another. However, during their alone time, Baro and Jinyoung have to act according to what the other members tell them to do.

B1A4 starts their clothes making challenge, an idea presented by Gongchan back in episode seven. The members decide, by a random ladder, which member will design for which child. After creating a portfolio, the members then are able to present their ideas to Ha Sangbaek, a famous designer. After presenting and discussing, the members are then given a mission to buy fabric of their choosing for their designs before going back to meet with Ha Sangbaek. In the end, B1A4 start the challenge to make their own clothes.

B1A4 continue the mission of creating their own clothes for the children. After coming back from Japan due to an overseas schedule, the members are split into two groups. The three members who went over to Eunsol and Hyunwoo first at the airport are one team and the two remaining members are a team. The three members, along with the children, go directly to Big Mama's house, a Korean chef, while the other two go to a traditional Korean market to buy ingredients for dinner. With two games, the wining team of each game gets to determine where they want to cook and with what ingredient. In the end, the members of B1A4 have a cook-off challenge amongst themselves in the two teams. The production, children, and Big Mama choose the winner by tasting the final dish. The losing team then has to drink a combination of things blended together and created by the winning team and the children.

B1A4 finally have their fashion show with guest MCs, Kang Seungchul and gagwomen Park Narae and Jang Doyeon. There are also guest judges as well, Ryu Seunghyun who is a head designer for a children's clothing company, Shin Youngsuk who is a designer for another children's clothing company, Won Myungho who is the president of a family look company, and Choi Sungjae who is a designer for a family look company. At the end of the episode, B1A4 bring the children back to their new dorm and discuss the day's fashion show as well as the ending of the show.

To start off their last day, B1A4 prepare an exhibition of pictures that were taken during the course of Hello Baby and display them on the sidewalk for people to see. For the last time, B1A4 tumble to earn money to buy toys for their children before moving to a different location. There they are surprised to be faced with a mini gathering of other fathers who are in their 20s. During the mini gathering they talk about their experiences of being a father, play games with the other fathers, and the children prepare a special stage for B1A4. To spend their last moments together, B1A4 then take the children to see the night view of Seoul at Palgakjeong, something that they haven't seen either. While there, they find the slow mailbox and decide to write letters to Hyunwoo and Eunsol that they will receive after a year. Finally, the members mail their letters and present their gifts to the children before sending them off.