Law authorities try to figure how how several notorious criminals suddenly die and are discovered to have no heart, lung or stomach, while critically ill patients suddenly recover from their maladies involving those major organs. When they call in one Smedley Throbbins, they get their answer: the man simply entered the 4th Dimension, surgically removed the organs in question without cutting through the skin, and then using the surgical techniques, placed them in the patient's bodies. He then disappears into another dimension so he can't be prosecuted for murder.