The Sherlock Society

Published in 2024, The Sherlock Society is a middle-grade mystery novel by James Ponti and the first installment in a series of the same name. The story follows 12-year-old Alex Sherlock, his older sister Zoe, and their friends, who form a detective agency for the summer. Their initial investigation into the historical cold case of gangster Al Capone’s buried treasure soon leads them to uncover a dangerous modern-day conspiracy involving environmental crime and corporate corruption in South Florida. The novel explores themes of The Transition From Self-Interest to Civic Responsibility, The Power of Collaborative Problem-Solving, and Redefining Friendship and Family Bonds.

James Ponti is a New York Times bestselling author known for his popular middle-grade mystery and adventure series, including the Edgar Award-winning TOAST series, which begins with the novel Framed! and the City Spies series, which begins with the novel City Spies. A Florida resident, Ponti grounds the novel in the state’s real history and locations, blending historical fact with fiction. The Sherlock Society pays direct homage to the classic detective tradition of Sir Arthur Conan Doyle’s Sherlock Holmes, updating it for a contemporary audience by equipping its young detectives with modern tools like drones and digital research skills alongside traditional deductive reasoning. The book was selected as a Junior Library Guild Gold Standard Selection.

This guide is based on the 2025 Aladdin paperback edition.

Content Warning: The source text and this guide feature depictions of      death and animal death.

Plot Summary

Twelve-year-old Alex Sherlock, his 13-year-old sister Zoe, and their grandfather are clinging to debris in Biscayne Bay after the yacht they were on, the Sweet Caroline, explodes. They are rescued by Marine Patrol officers. At the Marine Patrol headquarters, their mother, a lawyer named Melinda Lassiter, arrives. She is soon joined by Special Agent Dale Tyree of the Secret Service, who reveals he was already in Miami investigating the yacht’s owner, Morris Kane. Tyree offers the family immunity for their cooperation. While he is gone to make it official, Zoe negotiates immunity from her mother for any trouble they have caused.

The story flashes back to the second-to-last day of school. Alex and his friends Yadi and Lina, the only members of the Sherlock Society mystery club, are in the library. Zoe, upset that her parents will not let her go to a summer camp in Maine with her friends, interrupts them. Alex tricks her into participating in an escape room game, and though initially reluctant, Zoe becomes engaged in solving the puzzles. The next day, she proposes they turn the Sherlock Society into a detective agency. They create flyers and business cards, and Grandpa agrees to be their driver in his 1964 Cadillac convertible, Roberta.

Their flyers fail to attract clients, but Zoe receives a text from a potential client, “Desperate Dan,” who wants to meet about a missing person. At a Cuban café, they discover that “Desperate Dan” is their mother, who promptly shuts down the agency over safety and legal concerns. Dejected, the group returns home. Grandpa tells them a story about his early reporting career, explaining that a detective does not need to be hired to solve a mystery. He takes them to his storage unit, which he calls “the vault,” containing all the files from his 46-year career, including two cabinets of unsolved cold cases.

The group decides to investigate the legend of Al Capone’s million-dollar buried treasure. Grandpa assigns each member one of the “five Ws” of journalism to guide their investigation. They learn the treasure was buried before Capone’s trial for tax evasion. Clues from two sources, Capone’s gardener Tom Jackson and a waiter named Domenico DiMauro, suggest the treasure is protected by wild animals and is on an island located on another island reachable without a boat. After visiting Capone’s former estate, they interview Virginia Jackson, the gardener’s granddaughter. She confirms the treasure is not on the estate and shows them her grandfather’s plant diary and a botany book from Capone. The book contains an inscription with a Bible verse suggesting that the treasure will be found in a place dear to someone’s heart.

Lina discovers a hand-drawn treasure map hidden in the spine of the botany book. The map, created by Capone, is an overlay for the book’s frontispiece, an illustration of royal palm trees. The clues lead them to the old zoo at Crandon Park on Key Biscayne, where they find a small island in a lake that seems to match the map. However, Lina realizes the zoo was built in 1948, a year after Capone died, making it another dead end. Back home, Alex and Zoe’s father, a marine biologist, suggests they investigate the “Lost City,” Capone’s former moonshine hideout in the Everglades.

After three frustrating days of searching the Everglades with Yadi’s drone, the group stumbles upon a path that leads them to a three-acre island matching the description of the Lost City. They discover the surrounding water is poisoned and filled with dead animals. They find a pile of illegally dumped industrial waste, including three metal drums. Using the drone and Grandpa’s fishing rod, they collect video evidence and a water sample, which they report to the Miccosukee Police. The officer on duty admits they have limited resources to investigate. Zoe declares that they must solve this new, urgent environmental crime.

Dad’s lab analysis of the water sample reveals industrial chemicals associated with a printing press. A review of the drone footage reveals a missing hubcap and a coffee cup from Bailey’s Bait & Tackle Shop at the dump site. Posing as student filmmakers, the group convinces the bait shop owner to let them copy his security footage, which reveals a white truck with a “KC” logo that they trace to Kane Crystals, a sugar company owned by Morris Kane. Grandpa’s old colleague, Joe Moody, reveals that Kane is a crook who embezzles from his family’s newspapers by billing them for fake expenses, including a new printing press. To secure an interview with Kane, the group fabricates a high-profile documentary, creating a fake trailer and website to appeal to his ego. During the interview, Kane portrays himself as an environmentalist but is interrupted by his nephew, Aaron Pettigrew, the man from the bait shop footage.

Grandpa follows Pettigrew’s truck, which is missing a hubcap, to the Sabal Palm Yacht Club. Lina reveals she accidentally recorded the conversation between Kane and Pettigrew. To handle the recording ethically, Grandpa listens to it first to determine if it contains private information or admissible evidence. He initially lies that the recording is useless to protect Yadi and Lina, but later reveals to Alex and Zoe that it contains crucial evidence. The recording reveals that federal agents are planning to raid Kane’s properties and that Kane has ordered Pettigrew to destroy evidence by dumping it in the ocean from the Sweet Caroline. Alex, Zoe, and Grandpa sneak aboard both Kane’s sailboat and his yacht. They discover nothing on his sailboat, but Zoe accidentally leaves some belongings there. On the yacht, they     discover a hidden smuggler’s hold filled with counterfeit cash. They are trapped when two men, the Thompson brothers, board the yacht and take it into Biscayne Bay. The men set the counterfeit money on fire and escape on Jet Skis. The trio escapes the burning yacht just before it explodes.

The narrative returns to the present. Agent Tyree postpones the official interview until Monday, revealing “snags” in the immunity deal. At the Monday meeting, Tyree presents immunity papers for only Alex and Zoe, explaining that Grandpa has negotiated a deal to take full responsibility. The federal raids failed to find conclusive evidence, and the discovery of Zoe’s dive gear on Kane’s sailboat makes them the prime suspects. Zoe has a breakthrough, realizing the Secret Service’s case hinges on finding the counterfeit printing “plates” mentioned in the recording. Recalling the story of jewel thief Murf the Surf, who famously hid stolen gems by attaching them to the bottom of a boat, she deduces that Pettigrew used a scuba tank to attach the plates to the bottom of the sailboat’s hull, hiding them from the federal search. The plates are found, providing the evidence needed to arrest Kane and his associates, and the Sherlock Society is granted full immunity.

One month later, the Sherlock family, along with Yadi and Lina, are on vacation in the Florida Keys. Dad tells them Al Capone was known to use the area. He mentions there are shovels in a shed. Excited by the prospect of a new mystery, the group rushes off to investigate.