The vault of the Spencer Mansion is robbed, and the Bayport Police call on brother detectives Frank and Joe Hardy for help to tie up some loose ends. The teen sleuths soon find themselves in the middle of a major criminal investigation that takes them out of their hometown Bayport, and into New York City. But the pieces don't add up, and Frank and Joe find themselves embroiled in a drama of sinister proportions, and they begin to suspect the recent theft is somehow linked to something from the past. Source: Wikipedia, "The Hardy Boys: The Hidden Theft", available under the CC-BY-SA License.