Locked in his mysterious laboratory for weeks on end, the reclusive Dr. Jekyll works feverishly on a secret experiment, investigating the human soul and conscience. The good doctor believes that by isolating the good and evil impulses in the brain, he may bring about the end of mankind's wicked deeds. But the desire to play God backfires when Dr. Jekyll, under the influence of a chemical potion, becomes the fiendish monster, Mr. Hyde. Ashamed, but increasingly addicted to the hedonistic pleasures Hyde provides, Dr. Jekyll cannot contain the beast within.

Michael Rennie creates a tainted, guilt-ridden hero and multi-layered villain, breathing new life into the old Robert Louis Stevenson classic. Renowned British actor Sir Cedric Hardwicke is best remembered for his featured roles in Things to Come (1936), King Solomon's Mines (1937), and The Hunchback of Notre Dame (1939), and many others.