This is a low budget B movie with three interesting actors as its main attraction: Piper (who established himself well in They Live), Drago (who unfortunately never seems to get a role worthy of his abilities) and Heitmeyer (though inconsistent, she had her moments in TV's Earth Final Conflict). Piper and Heitmeyer must find a way to work around their differences and their sexual tension to defeat Drago and the army of alien virus carriers he is spawning through rape and murder.
The film starts out strong - with Drago getting into a fight with a fellow prisoner in a lunar prison and introducing the audience to his nihilism, sadism and psychosis. He dies in prison, but has been infected with an intelligent alien virus which reactivates his nervous system and uses him as a host to spread itself. Piper plays a member of an elite security force, and Heitmeyer plays a microbiologist brought in to study the virus as Drago begins his killing spree. The plot becomes more elaborate as the film progresses, and eventually takes on some details which really challenge believability. For example, it turns out that Heitmeyer vaguely resembes somebody who had been between Drago and Piper when they were in the academy together, and this is used as a device to permit a few gratuitous and silly bra scenes where Heitmeyer distracts Drago from his murderous intentions. Although the actors pull off their performances well enough, and the cinematography is relatively good for the genre, the plot is too thin to be sustained.
The bottom line is that this is not a suitable film for anybody who is NOT a fan of Piper or Drago. Heitmeyer fans will likely find this disappointing. It has little going for it besides decent acting, a reasonable script and a reasonable action-pace.