The Night Strangler proved almost as popular as its predecessor, garnering strong ratings and eventually prompting ABC to order a TV series.

[2] Reporter Carl Kolchak of Seattle, Washington is assigned by his editor, Tony Vincenzo, to cover a series of killings in which the victims, all exotic dancers, are strangled.

Berry uncovers further clues in an interview with Mark Twain leading to a Dr. Richard Malcolm, a surgeon in the Union Army during the Civil War, who was one of the original staff at Seattle's Westside Mercy Hospital; the doctor claims to have found immortality with the help of blood.

Kolchak and Louise, a psychology student who works as an exotic dancer to make ends meet, want to stop the killer before he completes his elixir and disappears for another 21 years.

In the Seattle Underground under the old clinic, Kolchak finds the preserved ruins of Westside Mercy Hospital and sends Louise to summon police.

Malcolm admits having first tried the elixir in 1868 and that he hoped to spread the knowledge of immortality, but in 1889 he started aging and his family died in the 1889 Seattle Fire.

A third film was planned, based on a story by Richard Matheson, but completed by science fiction and horror novelist William F. Nolan; the two share credit on the unproduced script.

Once again, Kolchak discovers a cover-up — this time involving a mysterious UFO, a nuclear power plant and important people being murdered and replaced by androids.