S01:E01 - So Long Old Paint // Trembly Assembly // Private I
Dennis meddles while helping Mr. Wilson paint his house, joins Henry at a car showroom, and play-acts as a tough private detective.
S01:E02 - A Visitor From Outer Space // Train That Boy // Genie Madness
An alien seeking peace lands in Dennis's room, while a train trip and a magical genie discovery lead Dennis and Margaret into more mischief.
S01:E03 - Cheer Up // Ghost Blusters // the Life You Save
Mr. Wilson slips on Dennis's skateboard, while the kids explore an abandoned house and Dennis steps up to save Margaret from danger.
S01:E04 - Shark Treatment // Jungle Bungle // Racetrack Menace
A beach film shoot draws Dennis's curiosity, while outings to a drive-through and a steeplechase race lead to more antics with Henry.
S01:E05 - All the President's Menace // the Love Rowboat // Wilson the Menace
Dennis visits Mount Rushmore, goes fishing with his parents at a local lake, and hypnotizes Mr. Wilson into acting like a nine-year-old again.
S01:E06 - Fishing for Trouble // Future Fortune // Time Bomb
Dennis goes fishing with Mr. Wilson, who tests PeeBee's new radio, while a stranger pays Dennis and Joey to deliver a mysterious package.
S01:E07 - Spa Blahs // Whale of a Tale // Disaster on the Green
Mrs. Wilson gifts George a health spa membership, while Henry is sent to Alaska and later must take Dennis along for a chaotic day at the golf course.
S01:E08 - Here, Kitty // Circus Berserkus // the Monster of Mudville Flats
Dennis brings home a stray kitten, joins Mr. Wilson for a circus outing with Joey, and later teams up with Tommy to trap the Mudville Swamp Monster.
S01:E09 - The Pride of Stardom // Space Menace // the Magic Flute
Dennis becomes a prop man at the community theater, tours Henry's aerospace company with friends, and later discovers a mysterious East Indian flute.
S01:E10 - Dennis' Yard Sale // the Abominable Snow Menace // It Came From Planet Dennis
Dennis tries to help the poor by selling household items, then causes chaos at a ski lodge and later teams with PeeBee to build a cleaning robot.
S01:E11 - Ruff's Hat Trick // a Moving Experience // Lemon-Aid
Dennis gets his father stopped by a policeman, while Mr. Wilson warns Dennis to consider his house off-limits and Margaret sets up a lemonade stand.
S01:E12 - Chitty Chitty Moon Walk // Wet N' Wild // Dennis at the Movies
Dennis watches a secret solar-powered moonwalker, while he and Joey build a raft and later attend a Cowboy Bob matinee together.
S01:E13 - The Supermarket // The Big Candied Apple // The Defective Detector
Dennis wreaks havoc at a supermarket, while the Mitchells visit New York and later the gang heads to the beach to search for hidden treasure.
S01:E14 - Henry the Menace // Come Fly With Me // Camping Out
Henry's father comes to visit, while Dennis and PeeBee take on a friendly challenge and Dennis later camps out with Joey in a backyard treehouse.
S01:E15 - Up, Up and Away // Going Ape // Dennis the Pirate
Dennis, George, Henry, and Joey enter a balloon race, while PeeBee loses control of a gas-filled balloon and Dennis later visits Pirateland with his parents.
S01:E16 - It's a Ruff Life // Professor Myron Mentalapse // Dennis Race 2000
Ruff and Joey have their brains switched, while the kids meet a quirky professor at a science museum and Dennis challenges Margaret to a soapbox race.
S01:E17 - A Better Mousetrap // the Wizzer of Odd // Canine Car Wash
Mrs. Wilson refuses to return until the mice are gone, while Dennis and Ruff are swept to Munchie-Land and Dennis later starts a dog washing business with Joey.
S01:E18 - Ride 'Em Cowboy // Tenting Tonight // a Hair-Raising Tale
Dennis visits his uncle's ranch, while Henry's company unveils a self-inflating tent and PeeBee creates a new formula that leads to trouble.
S01:E19 - Snowman Madness // the Invisible Kid // Home Destruction
Slippery ice disrupts Henry and Dennis building a snowman, while Joey gets soaked by PeeBee's solution and Dennis "helps" his father build a new playroom.
S01:E20 - Hopping Mad // Mayan Mayhem // the Big Power Trip
Dennis buys a magician's hat, while he and Mr. Wilson board the wrong vacation plane and later visit a city power plant with Henry and Ruff.