Pioneering rocket engineer Jack Parsons worked for the US government in the 1940s to rapidly advance rocket technology, with the goal of space exploration. His 1938 meeting with Ernest Donovan, a follower of Aleister Crowley, sparked a lifelong interest in the occult and the guiding principle "Do what thou wilt shall be the whole of the Law."

In 1930s Los Angeles, a janitor moonlights as a rocket enthusiast, navigating...