It's a remarkably solid sequel, though admittedly somewhat outlandish. Vincent Price – or rather, his voice acting – portrays someone who runs a thriving mining operation and finds himself wrongly accused of murdering his brother. He has just two hours before he’s scheduled to be executed when he enlists the help of a friend who created a clandestine drug capable of making people invisible; however, there's a drawback: prolonged use results in insanity. After utilizing this substance to break out of jail, he sets about discovering those responsible for his predicament among his inner circle, which includes Sir Cedric Hardwicke, John Sutton, and the striking Nan Grey. The watchful "Inspector Sampson," portrayed with skill by Cecil Kellaway, is also pursuing the unseen escapee, resulting in a well-timed mystery thriller featuring entertaining conversations and impressive effects that belie the fact it was produced early in World War II on a limited budget.

Source on TMDB