Seventh-grader Ace Ventura Jr. (Josh Flitter) emulates his long-missing father by becoming a pet detective, much to the dismay of his single mom, Melissa (Ann Cusack). But his skills prove useful when she's accused of stealing a baby panda and young Ace must clear her name. Ace soon deduces that the theft is the work of a famous animal thief. Now, it'll take all his sleuthing powers to track down the missing bear and bring the villain to justice.