Immortal was one of the first major films (along with Casshern and Sky Captain and the World of Tomorrow) to be shot entirely on a "digital backlot", blending live actors with computer generated surroundings.

In the city below, Jill, a young woman with blue hair and a fey countenance, is captured by agents of the all-powerful corrupt eugenics company that controls much of the government and private sector, who kidnap the alien refugees to experiment on them.

She is humanoid in appearance, but not quite human; her tears are blue and stain her pure white skin, and upon being examined by the company's scientists, it is discovered that her body's cells are no more than three months old despite looking and acting like a fully grown adult.

Elsewhere, Horus begins his search for a mate, but time is short as not only is his execution looming, but Jill herself will lose her unique ability to bear his child once she becomes fully human.

Meanwhile, a police inspector is investigating a series of serial killings in which the bodies of seemingly random individuals appear to have been torn apart from the inside out.

Eventually, Horus is successful and impregnates her in the nick of time, giving Nikopol's body back and leaving a parting gift by granting him the ability to move his heavy metal leg on his own.

In the film, Linda Hardy is dubbed by an English-speaking actress (Barbara Weber-Scaff), except for one piece of dialogue delivered in her native French.