April and Mark are looking for Professor Antrum who has been searching for Atlantis. Rumors indicate that crystals able to concentrate the power of the sun into a beam more powerful than a laser are hidden at the entrance to Atlantis. According to a cryptogram that entrance is on the property of an eccentric name LeGallows. Antrum is kidnapped by Thrush and recovered by UNCLE only to be re-kidnapped along with April and Mark.