Addison must solve the mystery of the scary sounds after Donnie convinces the other kids on a camping trip that the Headless Haunter is wandering through the park. | When swarms of mosquitoes mysteriously descend on the park, the kids’ summer movie night is in danger of being cancelled unless Add...

Addison and Alex dig up what they think is an Ancient Roman coin – then have a mystery to solve when it disappears. | When Addison and her classmates get an assignment to write about local news, Addison turns investigative reporter to crack the case of laundry that is going missing from balconies...

Addison’s excitement for show and tell at school turns to consternation when Donnie turns up with a robot that can do everything hers can do – only better! | Addison and Alex’s record-setting soap box derby car seems like a shoo-in to win the annual race – until something or someone makes it myst...

When Kevin’s new radio-controlled model car starts acting like it has a bad-tempered mind of its own, he believes it's haunted and asks Addison for help. | When helium balloons for Tess’s fashion show start inexplicably popping, she asks Addison to help stop the rest of the balloons from popping ...

Addison and her friends are distracted from making cool costumes for Ayrton Park’s Comicon when someone or something starts messing with recycling bins all over the neighborhood. | When an inflatable Pteranodon goes missing from the roof of Pizzamat, Addison and Alex are on the case.

Addison’s plans for a local winter Olympics are in jeopardy unless she can figure out why their outdoor ice-skating rink keeps mysteriously melting. | Addison fears that her family and friends have forgotten her birthday, so as a distraction, she follows a series of mysterious clues that take her...

Addison and Tess make a haunted maze for Halloween, but things take a perplexing turn when it seems that there really is a spooky presence on the loose within it – scaring away all their customers! | Addison is stumped when she awakens one morning to discover that Eureka and Gyro have disappeared...

When Mr. Tiggles goes missing, Addison must figure out if this is just a matter of a cat stuck in a tree, or a nefarious kitty kidnapping conspiracy. | When Mrs. Rorschach suddenly develops an allergy, every indicator points to Mr. Tiggles as the cause. Addison must solve the mystery before Mrs. ...

Ms. Bell has planned to surprise her students by hiding mammoth fossils in the school sandpit. But the surprise is on Ms. Bell when the fossils disappear. | When crop circles appear in Ayrton Park, Alex suspects visitors from the fourth dimension, but Addison begins sleuthing in search of a diffe...

When Addison and Tess find a note in a funny old pair of rummage sale pants, they think it's a clue to a stash of priceless hidden diamonds! | When the school mean girls, Katie and Dinara, start their own detective agency and solve a rash of neighborhood mysteries, Addison wonders if she’s lost h...

Addison and her classmates must play a piece of music written by an eccentric billionaire. He has promised to donate to the school’s music program – but only if Addison can correctly fill in the blanks in the sheet music! | Addison’s and Tess’s fairy garden attracts a mysterious glowing frog. Add...

When the fish in the local pond disappear, Addison and Tess fear they ended up as fish sticks in the school cafeteria. | Addison and Alex are afraid that Mrs. Rorschach is being intimidated by a shadowy pro wrestler named the Lucha Grandma and are determined to learn her identity and put a stop t...

When Alex receives an unsigned note from a "secret admirer", he calls on Addison to help him find out who thinks he’s so wonderful! | When it appears that a midnight vandal is damaging Max’s entry in the town’s "Most Beautiful Public Garden" project, Addison goes undercover ninja to save the day.

When an advanced computer is loaned to Ayrton Park Public School, mysterious cyber events happen around town. Addison wonders if the occurrences could be part of a world-wide-web… of mystery! | When a lost parrot appears in Ayrton Park, Addison must find its rightful owner by deciphering the bird...

Addison and Alex are filming a documentary about a "typical day in Ayrton Park" – but things quickly become anything but typical when a mysterious fog envelops downtown. | Addison is faced with a double challenge: solving a series of strange thefts in Ayrton Park, and then figuring out why the cl...