Wednesday Addams is set to present her experiment, where she uses her pet squid Socrates' DNA on Uncle Fester to show how humans can be improved (with the side effect of gradually transmutating Fester). However, she is dismayed when she sees her family arrive. Nonetheless, her work was noticed by scientist Cyrus Strange. Back at the Addams' home, Gomez worries that the children are drifting apart from him and Morticia, so he decides to take them on a family vacation. Before the family, Fester, Thing and Lurch head on a road trip across the United States, Gomez and Morticia are approached by a lawyer named Mr. Mustela, who claims that Wednesday was switched at birth and may not actually be an Addams, but they ignore him. On the road, the Addams family is pursued by Mustela and his employer's henchman Pongo.  PRE USED!!