Carl the Gardner grows odd plants for a rich Yankee woman Ellen Bennett living in South America while exercising a mental hold over her. All his previous employers died mysteriously.

Two brothers, scientists Scott and Tony Nelson, develop an amplifier which enables a person to enter a 4th dimensional state, allowing him to pass through any object. Scott experiments on himself and discovers that each time he passes through something he ages rapidly. He begins killing people, sucking out their life energies and regaining his youth as a result.

When a crooked sheriff murders his employer, William "Billy the Kid" Bonney decides to avenge the death by killing the man responsible, throwing the lives of everyone around him into turmoil, and endangering the General Amnesty set up by Governor Wallace to bring peace to the New Mexico Territory.