Cyd and Shelby take a bite out of the Big Apple when they use Barry's new invention to teleport themselves to the NYC Central Park Spooktacular only to end up trapped in a haunted house.
When Shelby's adventurous Grandma Rita comes to visit, the girls learn time travelers were responsible for setting up Shelby's grandparents and they jump to the 1950s to investigate.
When Cyd and Shelby go back to kindergarten to celebrate their friendship anniversary and relive the day they first met, they begin to change back to their five-year-old selves.
When the girls are assigned to do a report on the 1970s disco era, they decide to travel back and experience the 70s firsthand and land in the midst of turf battle between the disco and punk kids.
Cyd and Shelby discover a major clue to the future lab memory and it is somehow tied to Barry's science idol Janet Smythe, who also employs Shelby's dad.