Years after fleeing his ancestral home with his mother, Jason (Keith Mitchell) returns home to claim his birthright, only to find his way blocked by his evil cousin Thomas (Peter Arne). In order to reclaim his title, Jason must do battle with his cousin, who calls upon the members of the deadly Hellfire Club to stop him.

England, 1752. Young Jason accidentally blunders into an orgy being held by his father, Lord Netherden, leader of the infamous Hellfire Club, and gets a beating for his imprudence. His mother, disgusted by Lord Netherden's moral degradation, flees with the boy, but she is killed in a coach accident, leaving him to be brought up in Holland by Timothy, a family retainer. Some 15 years later, following the death of his father, Jason returns home as an acrobat in a traveling circus; but he finds that his Cousin Thomas has usurped his title and estate and has become president of the Hellfire Club. Searching for proof of his rights, Jason is aided by Merryweather, an attorney, and poses as a stable groom at his family estate, but he is discovered by Thomas and thrown into jail under sentence of death. Circus friends rescue him, however; he is reunited with his childhood sweetheart, Yvonne; and even the prime minister, who wants to disband the Hellfire Club, espouses his cause. Thomas abducts Yvonne, but Jason, disguised as a marquis, rescues her and mortally wounds Thomas. He then becomes the new Lord Netherden and marries Yvonne.