The 4D Build-Extending Blocks

Doraemon and Nobita decide to have a pillow fight which becomes noisy and causes Tamako to stop them. Doraemon concludes that if they can't play on the second floor then they will play on the third floor and takes out a new gadget: The Fourth Dimensional House Block. By placing a "Room Block" between the second and first floors, a new room will be created. Doraemon then inserts a block between the first and second block to create a new floor. They then had a pillow fight without annoying Tamako. After the pillow fight, Nobita decides to invite Shizuka over so that she can occupy the second floor. Doraemon then leaves to find his cat friends but not before telling Nobita not to use the gadget further for his own need.

Nobita ignores him and puts up a poster inviting people to their multi-floor house. Just then, Suneo shows up and Nobita invites him to occupy the new third floor. Gian soon comes and forces Nobita to create a new fourth floor for him as well. This event is torture for Suneo and Shizuka as Gian's song is disturbing them. Nobita decides to create three more floors and gives Suneo and Shizuka the seventh floor instead.

On the first floor, a man arrives inside and asks Tamako whether he can rent one of the rooms. Tamako gets confused which causes the man to take her outside and show her the poster that Nobita attached on the wall. At the same time, Doraemon arrives and they both realize that this is Nobita's doing. Tamako and Doraemon quickly head upstairs to scold Nobita. Nobita hears their angry calls and quickly adds the rest of the Room Block to prevent them from reaching the top floor. Soon enough, Tamako and Doraemon collapse under pressure on the stairs.

Nobita then enjoys his victory and the beautiful view outside when suddenly he gets the urge to pee. As the bathroom is only on the first floor, Nobita quickly rushes down the stairs. As he heads down, he reaches the floor where Tamako and Doraemon had collapsed and Nobita, afraid of his mom and is unable to endure anymore, wets his pants. Nobita begins to cry and blame his mother for making him pee, while Tamako scolds him for creating too many floors and storms off. As Nobita continues to bawl to Doraemon, Doraemon reiterates that he shouldn't have created that many floors.