Decadent is an atmospheric exploration, Lovecraftian horror that sees players take the role of John Lorn, a royal explorer and a veteran of the Great War, who has become an occultist. During one of his occult experiments he has become host to a mysterious parasite, one that gives him strange abilities at the expense of his sanity. As he follows the lost Miskatonic University expedition to find his missing son, John will walk the fine line that separates good and evil and sanity and insanity.