Who are the characters in tower treasure?

In "Tower Treasure," the first book in the Hardy Boys series by Franklin W. Dixon, the main characters are Frank and Joe Hardy, two teenage brothers who are amateur detectives. They are assisted by their friends Chet Morton and Biff Hooper. The story revolves around their investigation of a local treasure heist, leading them to encounter various suspects, including the mysterious figure known as the "Tower". The characters embody themes of friendship, bravery, and resourcefulness as they solve the mystery.