When Addison and Alex taste the new pizza that Mr. DiGiovanni has created especially for Tess's birthday, they find out it doesn't taste good at all.
Ms. Bell's wedding is in peril when a ghost scares away the customers from the beauty salon where everyone is getting ready for the ceremony.
Addison goes undercover when it appears that someone is stealing raspberries from the community garden.
Addison has to figure out why Alex can't kick a soccer ball nearly as well as he used to, in order to correct his game in time for him to pass the team tryouts.
Addison, Kevin and Tess are trying to make a rap music video for Ayrton Park's Summer Fest Movie Night, but a persistent very LOUD buzzing from above keeps ruining everything!
When Tess and Alex suddenly start getting electric shocks for no apparent reason, Addison has to solve the mystery.
During a summer heat wave, something or someone - perhaps a cryptid Camenel - keeps draining the water from the wading pool.
Ms. Bell's prized apple-hologram marble - a gift from her own favourite teacher at teachers' college - goes missing.
Donnie, the obnoxious class semi-bully seems to have developed psychic powers.
When Gyro the robot appears to be unhappy, Addison has to figure out what's wrong with her little friend.
When the honey in the community garden's beehive turns bright indigo, Addison is on the case to find out what's giving the bees the blues.
When it appears that half of the cookies Tess and Addison baked for a charity event go missing, the girls are mystified.
The annual winter carnival seems to be in trouble when Addison and Alex's yeti sculpture appears to have been vandalized... perhaps by an actual angry yeti!
When strange symbols begin turning up in Ayrton Park, Alex begins thinking that an alien invasion is imminent.
Addison has to find out what's wrong with Mrs. Rorschach's cat, Mr. Tiggles, when he becomes afraid of his own cat toys, especially the new fridge magnet mouse.
When a cryptic message turns up in a bottle in the Ayrton Park wading pool, Alex suspects it's from Ancient Egyptians or someone shipwrecked on a desert island .
The Junior Rangers weenie and marshmallow roast fundraiser is in danger of being shut down because of a ban on open flames.
When a geocached item seems to have disappeared along with the soil it was buried in, Addison is intent on finding out what happened to it.
When the drains at Pizzamat and Hang 20 start backing up, Alex knows exactly what's caused it - a sewer-gator or maybe a blob monster from outer space.
When Addison's mom, Detective Patel, comes to the school to talk about her work as a detective, she intrigues Addison and the other kids.
Addison has to solve the mystery of what's making scary sounds after Donnie convinces the other kids on an Ayrton Rangers camping trip that a mythical spook 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 Addison and her friends can figure out a way to stop them.
Addison and Alex dig up what they think is an Ancient Roman coin in the community garden - then have a mystery to solve when it unexpectedly disappears.
When Addison and her classmates get a school assignment to write about local news - and the news is that laundry is going missing from balconies around Ayrton Park.
Addison's excitement at bringing Eureka and Gyro in for a 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 shoe-in to win the annual race - until something or someone makes it mysteriously slow down to a crawl.
When Kevin's new radio-controlled model car starts acting like it has a bad-tempered mind of its own, he becomes convinced that it is haunted and asks Addison to help.
When helium balloons for Tess's fashion show start inexplicably popping, she is upset and asks Addison to help her figure out the cause and stop the rest of the balloons from popping before.
Addison and her friends are distracted from their mission of making cool costumes for Ayrton Park's version of Comicon when someone or something starts messing with recycling bins.
When an inflatable Pteranodon goes missing from the roof of Pizzamat, Addison and Alex are on the case to find it.
Addison’s plans for a local version of the winter Olympics are in jeopardy unless she can figure out why their outdoor ice skating rink keeps mysteriously melting and running away.
Addison fears that her family and friends have forgotten her birthday, so instead takes consolation in trying to solve a series of mysterious clues that take her on a wild goose chase.
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.
Addison is stumped when she awakens one morning to discover that Eureka and Gyro have disappeared without explanation!
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 has to solve the mystery.
Ms. Bell has planned to surprise her students by hiding mammoth fossils in the school sandpit for them to dig up. But the surprise is on Ms. Bell and her students when the fossils disappear.
When crop circles begin appearing in Ayrton Park, Alex suspects visitors from the fourth dimension, but Addison begins sleuthing in search of a different explanation.
When Addison and Tess find a note in a funny old pair of rummage sale pants, they think they may have found a clue to lead them 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 neighbourhood mysteries before Addison can, she wonders if she's lost her touch.
Addison and her classmates are tasked with playing a piece of music written by the local eccentric billionaire, who has promised to donate much-needed funding to the school's music program.
Addison's and Tess's fairy garden school project attracts a mysterious glowing frog, and while Alex thinks it's radioactive and Tess believes it's a magical fairy frog.
When the fish in the local pond all seem to disappear, Addison and Tess fear that they ended up as fish sticks in the school cafeteria's lunch special and set out to solve the mystery.
Addison and Alex are afraid that Mrs. Rorschach is being secretly intimidated by a shadowy pro wrestler named the Lucha Grandma and are determined to find out her identity and put a stop to her antics.
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.
Mysterious cyber events begin happening around town and 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 some way of returning it to its rightful owner by deciphering clues from the cryptic phrases that the errant bird utters.
Addison and Alex are filming a class-project documentary about a "typical day in Ayrton Park."
Addison is faced with a double challenge: figuring out who is behind a series of very strange thefts in Ayrton Park, and then when she does discover who the perpetrator is.
