The Patient in Room 18

While detective Lance is recouperating in a hospital due to mental stress from work, the head doctor and his patient in room 18 are murdered and $100,000 worth of radium goes missing. With the help of his former sweetheart (played by Ann Sheridan, who also happens to be a nurse in the ward), it is up to Lance to stop the string of murders and recover the missing radium. (Summary by Mentaculus)