An emergency call is received from a surveillance station overseeing the prison planet of Kayden Garth, indicating that the station may have inexplicably been dragged into the penal colony and its crew disappeared. A task force of four undercover agents is sent to Kayden Garth to investigate the source of the signal.

Kayden Garth is a role-playing game that is controlled in the style of Ultima, alternating an overhead world map to first-person dungeon crawling. The player assembles a party of four by picking each character out of eight possible alien races and eight classes, with some classes being available to certain races only. Some mutant races are able to cast psionic spells, including light, healing, teleport, attack spells and seeing the dungeon map. Combat is extremely simplified, taking place against one opponent at a time and only allowing a choice between attacking, casting spells or fleeing. There is no micromanagement of party members or their inventory.

The game includes a form of economy, with credits that can be looted from defeated monsters, bet in casinos and used to buy weaponry, shields, torches and rations. Light sources, along with light spells, are essential to the exploration of dungeons.