Vintage D&D Module Beyond the Crystal Cave
Beyond the Crystal Cave is a Dungeons & Dragons module set in the World of Greyhawk campaign setting. It is unusual among Dungeons & Dragons modules in that it encourages a non-violent approach (mainly parleying and true role-playing tactics) to achieving the module's goals. It is set in an old English milieu on Sybarate Isle in the Hold of the Sea Princes.
In Beyond the Crystal Cave, the player characters are hired to rescue a recently eloped couple that has fled into the Cave of Echoes. The heroes must solve the mystery of the Crystal Cave to enter Porpherio's Garden, a magical place located on the island of Sybarate where it is summer all year long. Experience points are gained by dealing with encounters verbally and intelligently, rather than through unnecessary violence.