# Frank Hardy — The Secret of the Old Mill character guide > Frank Hardy in The Secret of the Old Mill by Franklin W. Dixon. **Role:** major **Also known as:** Frank, Paul Blum, Blum **First appearance:** 0000-i-a-five-dollar-bill ## Snapshot The older Hardy brother, whose cool head and sharp eye for a bad bill turn a routine hike into a counterfeit investigation. ## Who they are Frank is the methodical half of Bayport's teenage detective duo, the son of famous private investigator Fenton Hardy and already a veteran of two solved cases. He is the one who notices the odd fumble when Uncle Dock offers reward money, and who insists on working their suspicions alone until they have real evidence rather than running to their father. His patience and instinct for small details drive the brothers deeper into the mill mystery. ## Relationships ### [Fenton Hardy](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/fenton_hardy) _family_ Father and son, with Fenton often guiding Frank in detective work. ### [Joe Hardy](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/joe_hardy) _family_ Brothers and close partners in solving mysteries, with Frank as the more cautious leader. ### [Callie Shaw](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/callie_shaw) _romantic_ Frank's steady girlfriend, showing mutual affection and support. ### [Tony Prito](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/tony_prito) _friendship_ Close friend and frequent ally in investigations, often providing local knowledge. ### [Uncle Dock](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/uncle_dock) _family_ Uncle and nephew, with Uncle Dock often aiding the boys with his mechanical skills. ### [Lester](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/lester) _friendship_ Friend and informant who helps the Hardy boys with local gossip and clues. ### [Chet Morton](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/chet_morton) _friendship_ Loyal friend who often joins the Hardy boys on adventures, despite his cautious nature. ### [Sleuth](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/sleuth) _friendship_ Frank's dog and loyal companion, often aiding in tracking and clues. ### [Fenton Hardy](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/fenton_hardy) _family_ Father and son, with Fenton often guiding Frank in detective work. ### [Joe Hardy](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/joe_hardy) _family_ Brothers and close partners in solving mysteries, with Frank as the more cautious leader. ### [Joe Hardy](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/joe_hardy) _family_ Brothers and close partners in solving mysteries, with Frank as the more cautious leader. ### [Uncle Dock](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/uncle_dock) _family_ Uncle and nephew, with Uncle Dock often aiding the boys with his mechanical skills. ## In the story ### [A Five Dollar Bill](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/i-a-five-dollar-bill) Older brother, dark-haired, observant; agrees to change the stranger's bill and later discovers it is counterfeit. ### [Counterfeit Money](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/ii-counterfeit-money) Frank is the primary loser of three dollars and feels foolish for being deceived. He examines the counterfeit bill and later reports the incident to his father. ### [The Hardy Boys at School](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/iii-the-hardy-boys-at-school) Takes the teasing in good part, discusses the motorboat purchase, and promises to play on Jerry's baseball team. ### [Another Victim](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/iv-another-victim) Notices Callie's distress, learns about Pollie's counterfeit fifty-dollar bill, and gives the bill to his father. ### [V: Curing the Joker](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/v-curing-the-joker) Suggests the hike and participates in the revenge prank on Chet. ### [The Old Mill](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/vi-the-old-mill) Leads the group and questions Stummer about the mill. ### [In the Mill Race](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/vii-in-the-mill-race) Observes the men at the mill and decides to approach the boy. ### [VIII: Joe's Courage](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/viii-joe-s-courage) Runs to the mill for help and assists in the rope rescue attempt, showing concern for his brother's safety. ### [The Rescue](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/ix-the-rescue) Frank plans ahead, races to the willows, and leans out to grab Joe and Lester, holding them until help arrives. ### [The New Boat](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/x-the-new-boat) Frank is thrilled with the new boat and takes the wheel first, then challenges Tony to a race. ### [A Man in a Hurry](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xi-a-man-in-a-hurry) Frank pilots the Sleuth, notices the approaching storm, and becomes suspicious of the stranger's story about a train. ### [XII: Seasick](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xii-seasick) Frank steers the boat, devises a plan to make the stranger seasick, and ultimately knocks him out. ### [Paul Blum](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xiii-paul-blum) Navigates the Sleuth through fog and recounts the capture of Paul Blum to his father. ### [Paul Blum](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xiii-paul-blum) Captured by the Hardy boys after attempting to hold them up; arrested for passing counterfeit money. ### [XIV: Con Riley Guards a Package](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xiv-con-riley-guards-a-package) Frank asks about Paul Blum and participates in the flattery of Riley, later learns of Blum's escape. ### [The Chase](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xv-the-chase) Frank leads the pursuit, uses binoculars to track Blum, and helps capture the fugitive. ### [The Chase](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xv-the-chase) Blum escapes jail, steals the Sleuth, and is captured after his boat runs out of gas. ### [A Plan of Action](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xvi-a-plan-of-action) Frank proposes the theory that the old mill may be a counterfeiting plant and suggests talking to Lester to verify their suspicions. ### [A Plan of Action](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xvi-a-plan-of-action) Paul Blum is safely in jail after being recaptured, but he refuses to talk about the counterfeit operation. ### [XVII: What Lester Said](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xvii-what-lester-said) Leads the questioning of Lester, gathering key information about the mill's operations and Dock's behavior. ### [XVIII: Suspicions](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xviii-suspicions) Observes Markel's suspicious package handoff at the train station and discusses the case with Joe; later expresses confidence in solving the case. ### [XIX: The Rug Buyer](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xix-the-rug-buyer) Returns from school to find Mrs. Hardy distressed; questions her about the rug sale and later visits the police station. ### [XX: A Note of Warning](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xx-a-note-of-warning) Reads the warning note and decides with Joe to investigate the old mill that night, planning to use Joe's resemblance to Lester. ### [At the Mill](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xxi-at-the-mill) Leads the nighttime approach to the mill, strategizing their route and coordinating the crawl across the open field. ### [Through the Roof](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xxii-through-the-roof) Leads the climb up the willow tree and the descent through the roof, demonstrating caution and strategic thinking. ### [The Alarm](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xxiii-the-alarm) Frank leads the investigation, observes the counterfeiting operation, and memorizes the New York address given by Uncle Dock. ### [Trapped](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xxiv-trapped) Leads the discovery of the counterfeiters' plant and participates in the raid. ### [The Reckoning](https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/chapters/xxv-the-reckoning) Frank recalls how he became suspicious of the mill when Uncle Dock offered counterfeit bills as a reward. ## Links - HTML: https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters/frank_hardy - Book: https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se - All characters: https://www.betterreads.dev/discover/the_secret_of_the_old_mill_se/characters