The game presents the player with three different mysteries to solve. It uses live actors and sets as the player assumes the role of veteran detective Sherlock Holmes, assisted by his longtime partner Dr. Watson, trying to collect clues by visiting various locations, questioning witnesses and suspects, and reading the included mock London newspapers.
The player controls Holmes' iconic smoking pipe like a mouse cursor and can move it with the D-Pad and confirm a selection with . The three cases can be played in any order. The game can be saved to and resumed from the console's internal memory.
At the beginning of each case, a full-motion video clip depicts Holmes and Watson meeting a client and learning a few background clues about the case. Then the player must choose a particular location or person from the directory or notebook to visit, read the London newspapers for clues, or ask one of the young "Baker Street Irregulars" to investigate. The object of each case is to gather enough clues in the lowest number of visits possible, then go before a judge who then asks the player to answer the important questions about the case. If the player is successful, Dr. Watson reveals the player's score, based on the number of visits it took to solve the case. The player can view a video clip set in Holmes' and Watson's study that reviews the events that transpired.
Besides witnesses and suspects, there are several general informants and locations that can be visited to provide additional expertise. Visiting an informant is sometimes necessary to provide a clue that leads to solving the mystery.
Henry Ellis: The foreign news editor of The Times and an expert on international affairs.
Edward Hall: A barrister who can be consulted for his legal expertise.
Quentin Hogg: A crime reporter for The Police Gazette and a former police inspector who possesses a keen deductive mind.
Sir Jasper Meek: A medical examiner who can be consulted for his technical analysis of cadavers.
H.R. Murray: A chemist who can apply forensics to examine physical evidence.
Disraeli O'Brian: The head clerk of the Office of Records, who can provide legal records.
Langdale Pike: A gossip columnist who covers London's social scene and knows all of the city's scandalous gossip.
Porky Shinwell: A former prisoner and the proprietor of the Raven and Rat Inn who stays connected to underworld dealings through his establishment's seedy patrons.
London Library: A large library full of valuable reference materials.
Scotland Yard: The city's police headquarters where Inspector Lestrade can aid with the investigation.
Somerset House: An archive of records including births, deaths, and records.
These icons appear on the Holmes' desktop and help the player gather clues and solve the case.
Returns to the Table of Contents, where the player can save the game, load a previously started game, or select a different mystery.
Opens the Notebook, which stores the names of people and places of interest.
Opens the Directory, a list of names of people and places in London.
Opens a list of newspapers, which can be inspected for clues.
After selecting a name from the Notebook or Directory, Holmes or Watson can travel to a location by clicking this icon. A video sequence plays each time the player visits a relevant person or location. Selecting an irrelevant location to visit results in a short audio clip of dialogue between Holmes and Watson and negatively impacts the player's score.
After selecting a name from the Notebook or Directory, opens a page from Holmes' file that contains background information about the given person or place.
Baker Street Irregulars
After selecting a name from the Notebook or Directory, Holmes can send the "Baker Street Irregulars," street boys employed by Holmes as intelligence agents. The boys can gather inside information that Holmes is unable to collect in a direct interrogation, but they cannot help with every subject.
After collecting enough clues, Holmes can visit the courtroom, where the player is asked questions to solve the case and given a score based on the number of visits taken.
From the Table of Contents, the player can select any of the three cases to play in any order, save the game in progress, or load a previously saved game from the console's internal memory. There is also a video introduction by Holmes and an "instructions" page that provides audio descriptions of the icons on the desktop.
A list of names of people and places of interest. At the beginning of the case, it already contains a list of items, but additional names can be added to it from the Directory. It can contain multiple pages of names. The player can select a name and then an icon to travel to the person or place to investigate, open a relevant entry from Holmes' file, or send the Baker Street Irregulars to scrounge for clues.
The London Directory, containing people and places, sorted alphabetically. The Directory contains many names, but it is up to the player to determine which are relevant to the current case. As with the Notebook, after selecting a name, the player can click an icon to travel to the person or place for an interview, open the subject's entry in Holmes' file, or send the Baker Street Irregulars to investigate. The player can also click the Notebook icon to add the name to it.
The Times, a newspaper that the player can scan for clues. Each case has several papers that can be inspected. Like the Directory, not all of the entries are relevant to the current case.
The courtroom can be visited after collecting enough clues to solve the mystery. If the player has not yet visited enough relevant locations, the judge tells Holmes to investigate more. Otherwise, the player is asked to pick the name of the guilty party from either the Directory or the Notebook. If the correct suspect is chosen, the player is asked to choose the motive from four choices and then asked additional questions concerning the case. If the wrong choice is made, the player fails the case and must start over from the beginning.
If the case is solved successfully, the player is given a score based on the number of resources used in the investigation, with the player achieving Holmes' score if the case is solved in the fewest amount of steps possible. After solving the mystery, Holmes and Watson summarize the case in a video sequence.
The first two cases are on the first disc, and the third case is on the second disc.
The Two Lions
This investigation takes place on 17 August 1888. Holmes receives a mysterious note on his door leading him and Watson to investigate the death of two lions who were part of a traveling animal show. At the same time, a mysterious death is discovered that might tie the two cases together.
To solve the case, the player must find who killed the lions and the motive, the accomplices and what they did, and who murdered Stephen Lyons and the motive and method.
The Murdered Munitions Magnate
This case takes place on 20 March 1888. Courtney Allen, a wealthy industrialist of a gun factory, is murdered in an alley just outside his office. Scotland Yard believes it was a robbery as certain valuable contents that Allen had on him were also stolen. As Holmes and Watson investigate, they learn of a secret government project that Allen's company was involved in and its possible connection to the crime.
To solve the case, the player must answer who murdered Courtney Allen and why, the significance of special project SP#10, what transpired at Spaniard's Inn, why Richard Camp visited the French Embassy, and why the cigarette found at the scene of the crime was pinched evenly all around.
The Pilfered Paintings
This case is set on 22 January 1891. A pair of paintings, from a recently famed artist known as de Kuyper, are stolen from the National Gallery just days before they were to be revealed to the public in an art show. The unusual circumstances in which the paintings were originally acquired by the gallery only deepen the mystery.
To solve the case, the player must identify who stole the de Kuypers from the National Gallery, who hired the thief and why, who murdered Matthew Cole, and what parts Pierre Donet and Sir Cofman played in the affair.
Sherlock Holmes: Consulting Detective Vol. III, featuring three more cases, was released for the IBM PC and Macintosh in 1993, but it was not ported to any consoles.