In a distant galaxy, the starship hunting the notorious Count Zarth Arn [Joe Spinell] closes in on a gritty target planet, only to be struck by a mysterious weapon that drives the crew near madness. Three escape pods launch as the vessel spirals toward disaster, and the ship is destroyed when it plummets through the planet’s atmosphere.
Smugglers Stella Star [Caroline Munro] and Akton [Marjoe Gortner] collide with the Imperial Space Police, led by robot sheriff Elle [Hamilton Camp] and Police Chief Thor [Robert Tessier]. They slip away by leaping into hyperspace, only to surface with the wreckage of the attacked starship’s escape pod and a disoriented survivor. The authorities track their trail and capture the pair, who are tried for piracy and sentenced to life on separate worlds. Stella escapes her prison, but Elle and Thor recapture her, only to reveal that the sentence has been canceled; she’s taken to an orbiting ship where she is reunited with Akton.
The Emperor of the Galaxy reaches out through the void, praising them for recovering the survivor and tasking Stella and Akton with locating a hidden weapon of immense power, concealed by Count Zarth Arn. They’re offered clemency if they help recover two more missing escape pods and the mothership, one of which may contain the Emperor’s only son, the young Prince Simon [David Hasselhoff].
Accompanied by Thor and Elle, Stella and Akton set out for the coordinates of the first escape pod. Stella and Elle land on a beach by shuttle, finding no survivors, and Stella is led to a fierce Amazon fortress where Corelia, Queen of the Amazons [Nadia Cassini], appears to be in league with Zarth Arn.Elle survives an ambush and makes his way to the throne room, seizing Corelia to secure Stella’s release; they escape as Corelia activates a massive robot that gives chase until Akton and Thor arrive to rescue them.
On a desolate, frozen planet, Stella and Elle investigate the mothership crash site, only to find no life among the wreckage. Back at the ship, Thor is revealed to be an agent of Zarth Arn, ambushing Akton and locking Stella and Elle out on the frigid surface as night temperatures plummet. Elle keeps Stella alive with his own energy until Akton revives, defeats Thor, and frees both Stella and Elle.
Approaching the third pod’s world, their ship is assailed by the weapon that felled the earlier craft. Akton steers the ship through the danger, saving everyone, and Stella and Elle inspect the pod wreckage, only to be attacked by cavemen who smash Elle to pieces and abduct Stella. The Emperor’s son Prince Simon [David Hasselhoff] arrives and rescues her by firing lasers through his eyes, but the cavemen press their assault until Akton appears to drive them off; he reveals they’ve landed on the Count’s weaponized planet.
They are brought to an underground laboratory where guards separate the trio. The Count himself appears and unveils his plan: lure the Emperor to the planet and use his weapon to self-destruct, annihilating the Emperor, the planet, and everyone else. Akton battles the two robot golems, winning but taking a fatal wound, as the Emperor arrives and fires a green ray from his flagship to stop time for three minutes, allowing the group to escape just as the planet disintegrates.
A monumental space battle erupts between the Emperor’s armada and the Count’s forces. The Emperor ramps up his strategy by ramming the Count’s space station with the Floating City in a dramatic, four-dimensional assault—Starcrash. Elle has been rebuilt by the Emperor’s engineers, and Stella and Elle pilot the Floating City toward the enemy station, escaping just as their own city collides with the Count’s, delivering a decisive victory.
Stella and Elle are rescued by Simon, and the two humans embrace as the Emperor delivers a triumphant victory speech.
