Serpent's Tooth is about a reptile creature, who's species spends their time searching the desert. In this post-apocolypse world they have gained a reputation as guides. Our hero is hired to guide a small party of searchers. The difference is that the leader of the party has 'a map'. The goal is a 'lost' city. Well not really lost, the impression is that there was only one survivor of the last expedition - the horse that the leader rides.