Among the oldest games in the Sherlock Holmes series, this is perhaps the most one closest to the spirit of the original books. A crime occurs and there is an obvious suspects that has the motive... but something doesn't fit. Go around the scenes and gather information that leads you towards solving the mystery. Collect clues, documents and testimonies and use them to find the correct answers to the questions that arise in relation to the crime.
This game is very good, especially considering it's a bit old now. Its stronger part is the gameplay, while graphics and UI design leave something to be desired. Also, there are a few parts (e.g. the forest part) where you may lose, without a checkpoint and no autosaves, which means that if you didn't save shortly before, you are screwed. There are some other minor annoyances such as having to remove the quickbar (can be done with a single button press), in order to go to the previous area or find a clue.
Although there are better options out there, this is a nice piece of game that you won't regret getting if you are out of detective games to play.