The story takes place in Britain, where Detective Brent Halligan, an inspector at Scotland Yard, investigates a brutal series of murders committed in England.

The investigation leads Detective Halligan into a mystery surrounding the demise of the British Order of Druids and eventually takes him on a trip through time itself.

Clues are mainly found by moving the computer mouse over various objects on the screen and clicking them to add them to the inventory or gain information about them.

Assisting him with his investigation is Dr. Melanie Turner, an anthropologist at the Oxford Anthropological Museum, who, along with historian Arthur Blake, discovers that the murders match the description of cannibalistic sacrificial rites performed by Britannic druids.

While investigating a lead regarding a group of neo-Druids called "The Circle", Halligan is captured and held prisoner by their leader, Lord Sinclair.

Halligan awakens at dinner and, unbeknownst to him, is eating human flesh which grants strength and power, but also makes them susceptible to brainwashing.

Halligan stumbles on the site of the ritual and attempts to disrupt it, but is interrupted by the demonic druid Serstan, who holds Turner hostage.

[9] A second game demo was released later that year on September 25, which included the time travel scene to prevent the ancient ritual which resulted in the creation of the Inheritors.

[13] In the German market, The Mystery of the Druids debuted at #29 on Media Control's computer game sales chart for March 2001.

[20] Writing for Golem.de, Thorsten Wiesner commented, "The exciting story and the atmospheric game design are big pluses, but deficiencies in control and some weak graphics are also clear negatives—with a little more care, The Mystery of the Druids could have been a much better title.

Brett Todd of Computer Games Magazine proclaimed it "poorly designed, ugly, and rife with bugs.

"[28] Computer and Video Games derided its "unimaginative settings and painful dialogue" as well as its inclusion of "some of the most ridiculously complex puzzle sequences to achieve even the simplest of tasks" before deciding that it has "very little appeal for anyone but the most patient and geeky PC-head.

[25] In retrospect, Martin Ganteföhr characterized The Mystery of the Druids as an important learning experience for House of Tales, despite its mistakes and many negative reviews.