The Monsters learn the value of teamwork when they are sent to the store for milk. One wants to be in charge, Six falls asleep on the departing bus, Four tries to stage a mutiny and Seven loses his head. But, in the end, they pull together and bring home - Belinda the cow!
It is bedtime and the monsters will not listen to their Mom and go to sleep. Pillow fights, conga lines and even a mosquito hunt is among their antics. But when Mom reads them a fairy tale (featuring the Monsters in classic roles such as Cinderella, Snow White and Goldilocks) they tumble off to sleep.
Irascible Four must always look after his little twin brother Five. But, when Five's behavior includes eating Four's favorite toothpaste and polishing his ankles with Four's favorite toothbrush, Four does the unthinkable when he thinks Five isn't his brother anymore and blurts out that he wishes Five had never been born. Seven tells Four that he hurt Five's feelings. Mama crosses her arms and is very unhappy. Five thinks he's a bad boy and a good boy. When Five disappears, the Monsters think that Five has gone to the hospital to "Give himself back!" when it makes Four cry. The hunt is on when Four learns that an annoying Five is better than no Five at all. When he comes home crying, he wishes Five hasn't been his brother anymore, and One, Two, Three, Four, Six, and Seven begin to cry. So it's up to One, Two, Three, Four, Six, and Seven to get Five back.
A neighbor drops her baby off and the monsters decide to take up the challenge of babysitting. They then do their best to feed, change, entertain, and eventually go try to find the baby. Yes, they even lose the baby all without waking Mom who is getting some extra needed sleep. It's a lot of challenging work for the monsters.
One and Six have different ideas of how to stage their Mother's Day Party. Tempers flare and One suggests that if Six can't go along with her plan, maybe she'd be happier with another family. Six goes off in search of a "new" family, winding up as the star attraction at the circus.
For Two, there is nothing worse than waiting for a special package. He waits and waits and waits while the other monsters are having fun. Trying to be helpful, Seven searches for the package only to lose his head at the post office. The head travels around the world, but gets back home just in time to personally deliver Two's package.
With the help of "Doctor" Three, the Monsters try to cure Two's cold so they can all go to the movies. After many hilarious remedies lead nowhere, they discover that Mom's advice of getting plenty of rest is the best cure of all.
When a new girl named Mary moves in next door the monsters are eager to get to know their new friend, but the monsters all end up trying to outdo each other in impressing Mary because they each want to Mary to be their best friend. Mary discovers the monsters arguing and solves the problem by telling the monsters they can all be friends.
The monsters decide to buy a puppy but are unprepared as to how much work is put into owning one. In the process they forget about Belinda.
When the power goes out in their house during a storm, the Monsters find themselves scared. Four makes the matters worse by trying to spook the others only to find out he is the biggest 'fraidy cat' of all. Pulling together, they learn to be brave and that sharing their feelings is nothing to be afraid of.
When Four decides to be a movie director, he orders the rest of the monsters to make a video with him. But, after trying unsuccessfully to bully them into doing action, he learns that simply being nice gets more results.
With the big soccer game coming up, Seven feels like he's more of a burden to the team than some help. The other Monsters try and get him to be a better player, but in the end, it is Seven who teaches them all to work as a team.
When Five finds a wallet full of cash in the park, all the Monsters make plans for the money that isn't rightfully theirs. When they agree to wait a week for the real owner to come forward, sparks fly between the Monsters over the money. They have to learn the hard way that honesty is the best policy.
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.
One develops a lazy eye and must wear a patch over her good eye so that it can get better. What could be worse? She cannot fly, which she loves to do.
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!
Seven eavesdrops on the others, learning their secrets so he can pretend to read their minds. Impressed, they arrange a big show for all the neighborhood kids, but of course Seven's act falls flat. He then admits he eavesdropped and apologizes to everyone.
After learning all about the moon from "Buzz" Three, Four decides to build a spaceship and go there himself. The others join in the spaceship they made, but their finished contraption won't go and lift off the ground. Four overcomes his disappointment, realizing that they still had fun, and learned a lot along the way.
The monsters wait impatiently for their cupcakes to finish baking. Since time passes more quickly when you are doing something, they partake of some typically bizarre monster activities, such as building an exact replica of the Taj Mahal in their backyard and swimming the English Channel in under 10 minutes.
Spurred on by hopes of winning a trophy and creamed corn, Six competes in a bowling tournament.
Two is trying to write a song for a contest and needs peace and quiet! His brothers and sisters are eager to help but being quiet is a real challenge for six rambunctious monsters!
Six wakes up from a bad dream and is too scared to go back to sleep. Each monster shares their worst nightmare and soon they are all shaking with fear. Mom reassures them that bad dreams are normal and can't hurt them, and the exhausted monsters fall right to sleep.
Six promises Mom she'll take out the trash this week, but instead she pawns off the chore on the other monsters. They simply stash the garbage bags throughout the house - out of sight, out of mind! When the whole thing blows up, Six must face the consequences of her broken promise to Mom, so then Six starts to cry.
During a baseball game the ball takes a bad hop and hurts One's wing. After a few days rest, One's wing is better, but she's afraid to rejoin the team. A talk with "Trot Along" Three convinces One that she's just got to "get back on that horse" and face her fears.
Mom is sick in bed and One promises to supervise the others in doing her housecleaning chores. When things start to go wrong, One doesn't ask Mom for help, preferring to tackle the problems herself. As a result, the monsters' cleaning efforts soon spin totally out of control and Mom must step in to restore order.
Similar to the story of Boy Who Cried Wolf, Two pretends to be injured after his stomachache is cured. But he soon realizes that lying about himself is not fun. Mom tells the story of The Girl Who Cried Sloth.
Two feels like his nose is an object of ridicule because, after Mary explains a story of Pinocchio, the other monsters mock him for how long his nose is.
At a baseball game a very loud Four annoys Six so much she wishes he couldn't talk at all. Her wish comes true when Four loses his voice and the monsters go on a search for it all over town. Back at home, Mom prescribes bed rest for Four, and soon his voice is back as loud as ever.
One decides to keep a crab as a pet and names him Buster. But soon, she realizes that Buster will be even more happier in his natural habitat.
The monsters notice the Zoo Panda is sad and lonely in a neglected habitat. The Zoo manager explains they haven't the resources to improve it. So the Monsters try to find ways to raise money, but everyone finds it silly when Seven collects Pennies.
Tired of sharing a room with her siblings, One gets her wish when the monsters' estranged uncle comes over and offers to swap his mansion for the monsters' home. At first, it seems that having a new home is great, but when the monsters didn't like having their own rooms, they decide to find their mom and want to tell her that they want to switch homes again. During their journey to find Mom, they fell down the laundry chute, entered a hall of mirrors, a large bathroom, got sucked into the air tunnels, entered a room where the stairway are upside down, a room with a trampoline and finally both encountered and chased by large orange cat but near escaping it, they decide to head back to their house and asked their uncle to switch back, but it was revealed that he was actually their mother in disguise and the mansion they lived in was only rented for one day.
When Five is having trouble learning how to somersault, his siblings try to give him advice the same way Mom usually does - by telling a story. They tell some crazy fairy tales but only when Mom returns home is the moral of the stories revealed - "try, try again". This inspires Five to try, try again until he accomplishes a perfect somersault.
The whole family is on a shopping trip to a big department store. Six isn't paying attention as Mom gives instructions, and when she gets lost she doesn't know what to do. Finally a security guard reunites the family and Six learns she should always listen carefully to Mom's instructions. Noticing what happened to Four, Six begins to cry about Four.
Three is jealous of his siblings, so he pretends to be a baby. Soon Three learns that everyone loves him for who he is.
Four and Five have several arguments which escalates into the two formerly inseperable monsters deciding they do not want to speak to each other anymore. Fortunately the ever wise Mama finds a solution by making Four and Five clean the shed. It isn't long before the two are up to their old selves and are laughing at each other's antics.
When it is time for the monsters to give some of their old toys away for charity, Six does not want to give away her rocking horse Sparkles. When her siblings tell her she has to, she decides to run away not wanting to part with the toy. This results in a search around Centerville for Six and her toy rocking horse Sparkles. The other six monsters start to wonder if it was right for them to tell Six she had to give up Sparkles when she wasn't ready, but when events lead up to Six seeing Mary's little cousin, Carrey play with Sparkles, Six begins to cry when Sparkles was in the water, so she decides for herself that she is ready to give the toy up by letting Carrey keep it.
A mysterious letter arrives for Pirate Captain Three, instructing him and his monster crew to solve a series of puzzles to find a buried treasure in their own back yard.
While planning a backyard camp out, One gets carried away with tattling on her siblings to Mom. She's telling on them for every little thing they do, so the other monsters leave her to camp out all alone. This isn't any fun, and One realizes that you can take 'telling' too far.
Three (as Captain Threemo, a parody of Captain Nemo in 20,000 Leagues under the Sea) uses his imagination with the other six monsters in a submarine while he is waiting for a submarine he ordered. Three speaks with a Cockney accent in this episode. He sounds a little bit like Roger Radcliffe and Skylar without his accent from Elena of Avalor.
Passing by a construction site, Two overhears a bad word. Repeating it back at home, he enjoys the shocked reactions of his siblings. Mom tells him a story about how bad words upset others and Two resolves to never say the bad word again.
Seven wants to play a new board game but doesn't want to read the game's rules.
It's bedtime but the monsters aren't sleepy. Four asks the magic Plooky to make everything backwards so they don't ever again have to go to bed. He wishes it can be daytime forever. When night turns into day, they run outside to play… right into a crazy backwards world! Soon everyone is wishing for things to be back the way they were.
Four accidentally leaves the water on in the sink and learns an important lesson on about how you should not waste water.
Four shows Five the difference between boys and girls when he finds him playing with doll figurines of a space man and a farmer's wife in the sand box; however, he is proven wrong three times (once, there are boys in Six's ballet class [not to mention the teacher is a man]; then, One is skateboarding; and finally, Two and Seven are knitting [not to mention Mom has a bowling ball]). Meanwhile, Three, who is a troubadour in this episode, tries to consolidate Four and Five to share their dolls. He sounds like singer Bob Dylan. His voice also sounds a little bit like Johnny Cash. He plays his mandolin when he talks. Nevertheless he sings too.