Classicly

The Metal Monster is a fantasy science fiction story written by Abraham Grace Merritt – known by his byline, A. Merritt – was an American Sunday magazine editor and a writer of fantastic fiction.

 Dr. Goodwin is on a botanical expedition in the Himalayas. There he meets Dick Drake, the son of one of his old science acquaintances. They are witnesses of a strange aurora-like effect, but seemingly a deliberate one. As they go out to investigate, they meet Goodwin's old friends Martin and Ruth Ventnor, brother and sister scientists. The two are besieged by Persians as Darius III led when Alexander of Macedon conquered them more than two thousand years ago. Closed in between the Metal Monster and the Persians, it falls to Goodwin and Drake to find a way to escape their predicament.