In "Nate the Great Goes Undercover," Nate the Great, a young detective, takes on a new case involving a missing painting. His friend, Annie, is worried about her prized artwork that has disappeared, and she seeks Nate's help to find it. As Nate investigates, he uses his detective skills to gather clues and interview suspects. With the help of his trusty dog, Sludge, Nate uncovers the mystery behind the missing painting, showcasing his cleverness and determination throughout the story.