Unjustly accused of his brother's murder, Geoffrey Radcliffe is given a chance to prove his innocence before going to the gallows. He receives an invisibility drug to aid his investigation but is unaware that it causes dangerous delusions of grandeur. As Radcliffe races against time to find the true killer, Dr. Griffin works to develop an antidote before Radcliffe goes insane. © 1940 Universal Studios. All Rights Reserved.