Kid detectives Jigsaw and Mila have a busy weekend when they are hired to find the owner of a lost purse, and then must solve the mystery of a missing dinosaur at their friend Bigs's birthday party.
Christina, Grant, Benjamin, and Katherine become gridlocked in a mystery that takes them on a hair-raising history tour of New York City's most famous landmarks to find a priceless missing part of history.
A posthumous letter referring to buried treasure convinces Gary that his grandfather did not die a natural death and, with his friend Brian, he sets out to find both the treasure and his grandfather's killer.
Mary-Kate and Ashley investigate when someone steals the cheer Ashley wrote and copies the dance moves the twins' squad is using in the Cheerlympics competition.
Andy and Tamika are keeping an eye on the house next door while their neighbors are away, but when strange and troubling things start happening inside the house, the police refuse to listen to the children.