|Richard Widmark||Lt. Cmdr. Clinton 'Clint' Reed M.D|
|Paul Douglas||Capt. Tom Warren|
|Barbara Bel Geddes||Nancy Reed|
|Walter Jack Palance||Blackie|
|Zero Mostel||Raymond Fitch|
|Tommy Cook||Vince Poldi|
After Dr. Clint Reed is called in to supervise an autopsy of a unknown man, he discovers that the John Doe died of pneumonic plague. Revealing his discovery to the mayor and city officials, Reed is informed that he has 48 hours before the public will be told about a potential outbreak. Joined by Captain Tom Warren and his wife, Nancy, Reed must race against time to find out where the unknown man came from.