Keeper of The Purple Twilight - Plot

Plot

Scientist Eric Plummer comes under the sinister influence of a creature from outer space, capable of materializing in human form, but lacking human emotions. As a prelude for the invasion of Earth by his kind, the extraterrestrial being Ikar studies the human race. The one thing he cannot comprehend is emotion. Meanwhile, obsessed scientist Plummer is nearing a nervous breakdown trying to complete a magnetic disintegrator that will convert matter into pure energy. The alien offers his technical knowledge of how to build a ray gun in exchange for the scientist's ability to feel emotions. Their experiment, however, has unforeseen consequences for both of them; a team of alien enforcers soon arrives to destroy both of them, as well as the scientist's girlfriend. As Plummer's weapon would aid Ikar's invasion force if completed, Ikar makes a deal with Plummer (who is not aware of this fact). He will help Plummer complete the invention; in exchange, Plummer will allow him to steal his emotions for a "test drive".

It is revealed that Ikar comes from a hive world with strictly defined roles, divorced from emotion and personal identity: big brains (like himself) that do the thinking; soldiers that do the fighting; and females that produce the offspring.

But due to the interference of Plummer's girlfriend Janet Lane, Ikar is unable to control or understand his emotions. This causes the experiment to backfire. Although in command of the scientist's emotions, the alien has great difficulty in understanding such things as love and beauty - concepts utterly foreign in his world. Ikar's behavior comes to the attention of his superiors, who dispatch soldier forms of his species to discipline him. Meanwhile, Plummer uses the data to harness a fantastic energy source, and fashions a weapon capable of destroying all life.

However, Ikar begins to feel emotions such as anger, and desire for Janet, eventually returning the scientist's emotions to him. Ikar is now being pursued by his own species, as a threat to the planned invasion. It is revealed the aliens' homeworld is overpopulated, and they have chosen Earth to be their new home. In the end, Ikar kills two of the soldiers, but is disintegrated himself before Plummer destroys the last soldier. Doctor Plummer destroys his weapon, erasing all traces of his work and evidence of the aliens.