In the realm of Sosaria, a land divided by a thousand years of agony brought about by the malevolent sorcerer Mondain, a lone hero capable of turning back the tides of darkness has finally emerged. That hero is you. Your mission, a slight variation on the standard kill-the-evil-wizard theme, is to assemble a time machine, go back in time before the evil wizard developed unstoppable power and, then, of course, eliminate him.

Ultima I is a remake of the classic RPG Ultima from 1981. You must travel to another world and save the land Sosaria from the evil wizard Mondain. The game features tile-based top-down overworld graphics and first-person perspective pseudo-3D dungeons.

The original Ultima was re-programmed using assembly language, with updated graphics, minor changes in towns' and people's names, and some different puzzles.