The Sinister Secret of Saltmarsh is a module for the Advanced Dungeons & Dragons (AD&D) roleplaying game, written by Dave J. Browne with Don Turnbull. The module details a mysterious abandoned mansion at the edge of a town called Saltmarsh, and the secrets contained therein. The adventure is set in the World of Greyhawk campaign setting. The Sinister Secret of Saltmarsh received positive reviews from critics. Plot summary The Sinister Secret of Saltmarsh can be played by five to ten characters of 1st–3rd levels. The module includes optional pre-generated first level characters for use by the players. The scenario is the first of the Underwater (U) series of modules set in Saltmarsh, and details a ghostly ship and the haunted mansion of an evil alchemist. The module sleeve contains the following description: The module is divided into two parts, The Haunted House and Sea Ghost, which are intended to be played consecutively. The first part is set in the town of Saltmarsh and deals with unraveling the secret of the haunted house that lies on the edge of town. The abandoned, dilapidated mansion of an evil alchemist has been the subject of rumors about hauntings and treasure. The second part of the module follows on from the first, expanding on the concept. Publication history The Sinister Secret of Saltmarsh is the first installment in a series of three modules designed and developed in the United Kingdom, for beginning adventures with AD&D rules. The adventure was written by David J. Browne with Don Turnbull, and published in 1981 as a 32-page booklet with an outer folder. The publication contains large-scale maps, a full background story, and detailed encounter descriptions for the players and Dungeon Master (DM). The module serves as the introduction to an underwater campaign set in the town of Saltmarsh, which the DM can design from the guidelines provided. The next two modules, Danger at Dunwater and The Final Enemy, continue on from this adventure. Reception The module was positively reviewed in Issue No. 35 of White Dwarf magazine by Jim Bambra, who scored it 9 out of 10 and described it as entertaining and interesting. Bambra criticized how the first-level characters provided with the module come equipped with magic items: "I fail to see how this can be justified, as the module is not difficult enough to warrant the bestowal of magic before play even begins. Magic items