Osomatsu and Choromatsu mind Chibita as babysitters, but grow bored and decide to have a mysterious dog take the heed instead. Meanwhile, Dekapan creates a robot powered by spare change that inadvertently leads to disaster in the hands of the sextuplets.

Iyami attempts to con Osomatsu, Choromatsu, and Chibita out of their hard-earned money at his fishing pond with a rare fish that gives them all their money back if caught. Later, Chibita plays the role of the leader of a gang of thieves who targets Osomatsu for discovering their misdeeds.

Totoko's grandpa enlists the help of the sextuplets to stop Chibita and his gang of feral cats from attacking the fish store. Later, Iyami and Chibita fly around town in a helicopter to cause mischief amongst the locals.

A housework robot (shaped like Chibita) causes havoc amongst the Matsuno family when he malfunctions. Meanwhile, Iyami runs a scam out of a laundromat to catastrophic failure.

Iyami and Chibita feign construction workers to scam the sextuplets out the their money by making a paid shortcut to school. Later, a camera company offers a cash prize for whoever can photograph a face-making man without any made faces, leading the sextuplets and Chibita to try to claim the reward.

Spooky things seem to be happening around town, leading the sextuplets to discover a secret of their own appearance. Meanwhile, Chibita challenges the brothers to a martial arts battle.

Iyami scams the sextuplets with a magic kettle, actually utilizing Chibita as the secret inside. Later, Chibita and Bokeo get revenge on the sextuplets for harming their frog friend.

Chibita appears alongside Totoko wearing a strange hat that when removed, changes his temperament from good to bad, leading to chaos amongst the Matsunos. Meanwhile, Chibita goes boar hunting and encounters the sextuplets and Iyami.

Osomatsu visits dentist Iyami's office for a toothache, but due to an unpaid bill, assists him in fixing up the mouth of Dekapan's crocodilian "son". Later, after Chibita's mosquito colony is destroyed by the sextuplets, he and Iyami create a watermelon-shaped bomb to enact revenge.

Chibita, with the help of his scientist uncle, devise a plan to shrink the sextuplets down to flea size so that he will no longer be shorter than them. Meanwhile, a roaming minstrel and Chibita team up to enact revenge on the sextuplets with their army of cats.

A wealthy couple pay the sextuplets' parents to loan one of their boys out to them as a paid son, but the love they have for Osomatsu and Choromatsu is much too young for them. Meanwhile, Chibita drinks an invisibility potion and causes mischief.

A new girl moves into the neighborhood, and the sextuplets try to put the moves on her while confusing her dad for their eerily-resembling dog. Later, a crime family that Chibita is a part of has business with the sextuplets, climaxing in a rainy nighttime brawl.

An apple-headed doctor conducts an experiment on the sextuplets, but his seemingly strange mood swings are more than meets the eye. Meanwhile, Iyami works as a bespoke clothing designer for the Matsunos, but suspicions are aroused when the family's Children's Day koinobori goes missing.

Ninjutsu master Iyami insists the help of his disciples Chibita and Moguramaru to get revenge on the sextuplets. Later, Chibita attempts to thwart Totoko's run as Class President.

Chibita takes the place of Dekapan's trained dog "son" when circus ringmaster Iyami buys him for his circus. Later, a student with a padlocked hat transfers to the sextuplets' school, leading to a mystery of his identity.

The Matsunos take a trip in a wacky inventor's time machine to the age of the dinosaurs, where they meet their friends' prehistoric counterparts. Meanwhile, neighbors Iyami and Chibita go to war with the Matsunos over trash disposal.

Chibita falls in love with snooty Chikako, but the sextuplets' faulty attempts at woo cause more than trouble for the little lovebirds. Meanwhile, the sextuplets watch over a sleepwalking boy who becomes violent when awoken.

A Santa Claus-like figure arrives in the town, in actuality a persona put on by burglar Moguramaru to hide stolen goods. Later, deranged dentist Chibita enacts periodontal violence against people with better teeth than him.

The sextuplets become victims of a vindictive clothesless Chibita, who tries to steal their clean clothes. Meanwhile, the Matsunos offer Dekapan a place for his pig "daughter" to stay, but Chibita falls in love with her without knowing she isn't human.

The sextuplets' father invites work friend Iyami over for dinner, but chaos ensues in response to his disruptive behavior. Later, Chibita attempts to sneak onto an ocean liner under the guise of a sailor.

Iyami runs a "genuine" French restaurant with Chibita, and receives criticism for his poor service and lack of research. Meanwhile, Mr. Matsuno resigns from his position as patriarch, and runs away.