Sanitarium patients are mysteriously dying and being drained of their blood. Lamont Cranston and Margot Lane are summoned by the head doctor and arrive to find him murdered. The lab assistant accuses the duo of the doctor's death, but it is he who is draining the blood from the dead patients to sell it back to the hospital's blood bank.

During a cave tour, several students fall down a pit when the rail gives way. When a rescue team goes down, they find no bodies. The Shadow and Margot Lane investigate and discover a secret ruby mine deep below the caverns where the students have been kidnapped and are being used as slave labor.

After a professor is fired dishonorably from the faculty, he seeks revenge by planning to set off a bomb at the chapel during graduation day.

A mummy's curse seems valid when a strange death ray kills those who enter a Egyptian exhibit at a museum.

The Shadow foils a plot to rob a diamond mine.

Enemies of the United States have developed a germ that could wipe out the entire army, eventually leaving the U.S. open to invasion. It is first tested out at a barracks near New York. The Shadow must hurry and find out who is behind it and if a cure is available.

A killer in prison manages to enact his revenge on those who sent him up by placing their dead bodies in a wax museum.

Unknown to the passengers, munitions for a band of revolutionaries are being smuggled on the luxury steamship "Amazon." When the conspirators find out that their plans might be thwarted, they plan to blow up the ship, killing those on board.

The Shadow and Margot visit an island to find out why a dozen ships have vanished in "The Graveyard of the Pacific."

When "Singing Jim," a blind street singer, is killed, The Shadow goes after a band of extortionists who prey on the city's street beggars