A giant wooden apple on the fruit store sign falls off and no one knows where it went.//When Mr Frumbles newly painted green Pickle Car mysteriously disappears, Huckle determines he will find it and solve the Mystery of the Pickle Car Puzzle.

When Huckle, Lowly and Sally discover a missing wheel by the roadside, Huckle determines he will solve the Mystery of the Missing Wheel by figuring out what the wheel is missing from.//Several Busytown characters are dismayed to discover blue paint stains on the back of their clothing. Huckle sets out to find the bench in need of a 'wet paint' sign.

When a lost parrot shows up at the park, Huckle and Lowly decide to find its owner.//When the gang find strange footprints, Sally fears they were made by a monster. Huckle assures her they werent and announces hes going to prove it by solving the Monster Mystery.

Two identical tanker trucks pull into Gramps Gas Station at the same time. Shortly after, Huckle and his pals notice cars spewing bubbles and conking out. Huckle and his team solve the mystery by finding out bubble bath soap was pumped into the gas station tank by mistake.//Huckle, Lowly and Sally find an abandoned egg in the park. They search for a nest that has similar-looking eggs.

Regardless of Hilda Hippos photo of a ghost in the mansion by the lighthouse, Huckle sets out to prove there are no such thing as ghosts by solving the Mystery of the Lighthouse Ghost.//A sign directing customers to a sweet corn stand comes loose and swings upside down so the arrow points the opposite way.

Busytown pedestrians are getting their feet stuck in purple goo. In solving the mystery, Huckle notices these sticky puddles always appear under toothpaste billboards.//The kids help decorate used cars for Jack's big sale. Suddenly, all the helium balloon go missing...and so does Pig Won't

Hilda invites her friends over for muffins, but someone keeps taking them, one by one. Huckle finds clues that reveal the culprit is getting in and out of the house without touching a door or the floor.//When Huckle and Sallys dad finds a stack of cans in his store toppled again and again each morning, Huckle determines to solve the Crashing Cans Mystery by figuring out who is toppling them and how.

When the cake Huckle, Lowly and Sally plan on using in their Science Fair exhibit mysteriously disappears from a locked room, it begins to look like the culprit was invisible and could walk through walls.//Sally's scooter vanishes. Knowing that the kickstand sometimes fails, Huckle concludes that it must have rolled down the sloped street.

It appears a litterbug is dumping garbage on Mulberry Road. Huckle decides to solve the mystery of who it is by looking for clues about the culprit in the discarded trash.//Giant footprints, squashed car tops and broken tree tops have the Pig Brothers convinced giant robots from outer space are the cause.

When no one can find where Junior monkey went, Huckle, Lowly and Sally are saddled with his baby sister while they try to solve the Missing Monkey Mystery.//Pig Will and Pig Won't invite their friends to become members of their secret club.

When first home plate, then a bunch of other playground items start mysteriously disappearing, the kids are convinced its the work of some mysterious Playground Grabber.//En route to Mr. Fix-Its shop to have his broken portable video game repaired, Huckle, along with Lowly and Sally, is surprised when the clocks around them suddenly go crazy causing all kinds of confusion.

When the mouse family discover someone, or something, has taken a big bite out of their cheese car, Huckle promises to figure out who is putting the bite on the mouse family.//The kids witness someone rescuing Granny Goat from the train tracks. After the train passes, the hero is gone. Granny Goat didn't even get a chance to thank him.

For some strange unknown reason, every loaf of bread in Busytown is hard as cement!//On the outskirts of Busytown, the center line on the road suddenly goes twisty. It confuses drivers, causing them to veer off the road.