After his African adventure in "Ace Ventura: When Nature Calls," Ace returned to Florida, married girlfriend Melissa (Ann Cusack), and became the doting father of a baby boy. Never one to sit still, Ace’s curious nature took him on another remote case, never to be seen or heard from again. Now a zookeeper and single mother, Melissa struggled to put the past behind her as she and Ace Jr. (Josh Flitter) created a new life together. Much to Melissa’s chagrin, Ace Jr. has followed in his father’s footsteps, working as a pet detective for fellow classmates' missing pet cases. When a master animal thief abducts a baby panda, Melissa is wrongly arrested for the crime. Ace Jr. jumps into action. Now, with the help of his friends Laura Wilson (Emma Lockhart) and tech wizard A-Plus (Austin Rogers), Ace Jr. must bring the thief to justice.