A necromancer named Zharradan Marr has been gathering a small army and is particularly feared as a practitioner of marrangha, a type of black magic that involves the transformation of limbs and organs from one creature to another.

Aboard the Galleykeep Marr reveals the creature's identity and demands that he surrender Grog's box, which contains the Vapour of Elven Magic.

There are several diversions, such as the Testing Grounds where crew for the Galleykeep are recruited, but although they have a long decision tree all paths lead to death or failure.

At one point in the story the character finds a pendant that allows the player to locate secret passageways when used, achieved by adding 20 to any reference when it begins with the phrase "You find yourself..." Reference 213 commences with "You reach...", but adding 20 leads the player to a paragraph that states a secret door has been found, thereby allowing game progression.

Reviewer Stephen Bond stated that this feature was unique in that it was the only aspect of a story in the Fighting Fantasy line or any other that offered the player a chance to make a truly original choice, as opposed to taking one of several pre-programmed options.

[4] The Encyclopedia of Science Fiction comments on the experimental nature of some of the later volumes in the Fighting Fantasy series, naming Creature of Havoc as an example.

It will be written by David N. Smith, directed by Richard Fox and will feature Rachel Atkins returning to the role of Vale Moonwing from FoxYason Music's first release based on The Warlock of Firetop Mountain, sub-titled The Hero's Quest.