The player assumes the role of officer Don Jonz in Orion United Forces, who is starting a vacation in the planet Eternam.

[2][3] After arriving on the planet and changing into a costume of barbarian warrior, Don Jonz learns that his archenemy Mikhail Nuke has taken over Eternam.

The game is hampered by the fact that while it is structured as a point-and-click adventure, it lacks mouse support, requiring icons describing possible actions to be activated by keyboard commands.

Later the same engine was used in Shadow of the Comet, and in the CD version mouse support was added, to remove this limitation.

[5] Computer Gaming World in 1993 called Eternam "a first-rate adventure", with "hefty doses of humor" in a "remarkably compelling story".