EDITOR’S NOTE: The Black Pit of Dr. M was on Chiller Theater on Saturday, February 4, 1967 at 1:00 a.m. It was also on the show on August 10, 1968 and May 20, 1972.

Misterios de ultratumba was released as The Black Pit of Dr. M in the U.S. and it’s a movie that explores man’s fascination with what comes after this world.

Dr. Mazali (Rafael Bertrand) and Dr. Jacinto Aldama (Antonio Raxel) make a bet with one another: whoever dies first will return to tell the other what happens after death. Aldama goes first and appears to Mazali during a seance, telling him that within three months, he will know everything about the afterlife.

Aldama’s ghost leads Patricia (Mapita Cortés) — also his daughter, but that’s a spoiler — to the insane asylum Mazali leads. The older doctor falls for her, but she and an intern named Eduardo (Gastón Santos) are in love. He also lets another inmate out of her cell and she instantly burns an orderly with acid right to the face. She’s murdered, Mazali takes the fall and heads to the gallows, proving that he will indeed soon know the afterlife.

While most early Mexican horror repeats the Universal horror movies and most Americans only know lucha movies to be the rest of the genre output from south of the border, the truth is that there are moments of sheer gothic dread for those willing to look. I’d definitely recommend this movie — the opening with the mental patients filling the frame is harrowing and a man rises from his grave in an incredibly unsettling fashion — as well as Hasta el Viento Tiene Miedo.