Publisher's blurb: Expanded travel and discovery for your Tomb of Annihilation game! This is another entry in a series of supplements that seeks to provide bite-sized rules and adventuring options to help flesh out your Tomb of Annihilation game. In this supplement: Give your players the ability to discover teleportation circles in canonically reasonable locations, with information on who has knowledge of their existence. Find new hazards and means of travel with the Underchult - haphazard, oft-flooded tunnels that can sweep your party to places unknown with dangerous underground currents. Rules for discovering, navigating, and travel pace in Underchult. Includes quick tables for randomly creating your own Underchult tunnels and cavern systems.