When Four wins his brother Five a pet turtle at a fair Five and the turtle share a bond and become inseparable. Five even names the turtle Sam and goes as far as to give knit him a sweater, but during a bath time mishap Five thinks that Sam has gone down the bathtub drain. Five and his brothers and sisters explore the city drainage system to find Sam. When the reach the end of the line at the ocean they think that Sam has gone to his final reward. The family hold a memorial service and Five tries to deal with the loss. It isn't until they realize that Two is missing from the memorial service that they find out what really happened. Sam had fallen out the window and had climbed back in. Five and the others find him on Two's stomach. Two ended up with his nose stuck in the bath faucet and with no one to help him out he had simply fallen asleep.

It's Mary's birthday and the monsters wanted to make the biggest surprise ever for her. However, Seven is fascinated with Monster Marbles after seeing a commercial for the product on TV. When the monsters go out to buy a present for Mary, Seven uses the money to buy the marbles. But soon, he decides to come clean and realizes that the marbles aren’t as great as they were advertised.

Six is mortified to learn before a big ballet recital she is losing a baby tooth. She tries to save the tooth with the help of her six siblings, but it's no use. She says that if she would be the swan than the ugly duckling. After Mom tells Six the story of the Tooth Dwarves, and when she lies down in bed, Six starts to cry first before Mom tells the story. Six learns everyone loses teeth and that the show must go on!

One just loves to play baseball with Billy. But why doesn't Billy notice? Six comes up with a plan to make One more of a girl but that doesn't seem to help anyone, especially the baseball team! After trying to play baseball in a dress, One realizes it's better (and safer) to be herself.

Two is lacking in confidence prior to appearing as a contestant on his favorite game show. But he learns that with experience and family support that he can achieve his goals by relying on himself.

An elephant named Wendy from the zoo follows Four home. Four decides to hide Wendy for good before the rest of the family sees him, because zoo animals are not allowed in the house.

Seven teaches everyone about fire safety after his lessons from Chief Lubomir. Number one: Always know how to detect smoke and gas. Number two: When fire is seen, get in an orderly line and walk to the nearest exit. Number three: Get in line and stay in the line in orderly fashion. Number four: Always remain calm. Number five: Don't go in unless the firefighter says it's safe to go back in. Then the monsters skills are put to the test when Two smells real smoke coming from the kitchen.

The monsters decided to travel around the world using a hot air balloon, but Mom is angry because she discovers that the monsters decided to make the hot air balloon out of their house.

Four helps Five prepare for a pie eating contest, but it ends up making Five and himself incredibly unhealthy and sick.

Four and Five learns a lesson about making practical jokes too far. They learned it after a pretend alien threatens to abduct them.

Four is frustrated with his brothers and sisters and wishes it were just him around and not them. His wish comes true, but very soon, he begins to miss them and regrets his wish.

The Monsters are charged with cleaning the basement, but they get a little distracted! They pretend they are living in a world of superheroes and villains and make a bigger mess than when they started. They learn that sometimes it isn't a good idea to get so carried away!