Chick Young (Bud Abbott) and Wilbur Grey (Lou Costello) are baggage porters in LaMiranda, Florida. They deliver crates to MacDougal's House of Horrors museum that contain the remains of Dracula (Bela Lugosi) and the Frankenstein monster (Glenn Strange). Wilbur discovers they are alive and is hypnotized by Dracula. Both creatures escape and Mr. MacDougal (Frank Ferguson) accuses the delivery men of theft and has them arrested.
Dracula and the monster meet with Wilbur's girlfriend Dr. Sandra Mornay (Lenore Aubert) at a castle on a remote island. Dr. Mornay has been posing as Wilbur's friend to gain access to his brain, which she plans to transplant into the monster's head. Wilbur replies, "I've had this brain for thirty years. It hasn't done me any good."
Joan Raymond (Jane Randolph) bails the boys out of jail, as part of an insurance company investigation, but they believe Dr. Mornay helped them. Living across the hall is Larry Talbot (Lon Chaney, Jr.) the Wolfman who wants to destroy Dracula and the monster. Larry says, "Last night I went through another one of my horrible experiences. Many years ago I was bitten by a werewolf. Now whenever the full moon rises I turn into a wolf myself!" Wilbur believes the Wolfman, but Chick thinks they are both crazy and says, "That's alright. I'm a bit of a wolf myself."
The next evening, Wilbur, Chick, Larry, and Joan go to Dr. Mornay's castle for a costume ball. They meet Dracula, who is dressed as Dr. Lejos.
Larry: "So! We meet again, Count Dracula."
Wilbur: "Yes. That's who he says you are."
Dracula: "Oh. My costume perhaps?"
Chick: "No. Talbot here thinks you're the real thing!"
Wilbur: "Uh-huh. Right out of McDougal's House of Horrors."
Dracula: "What an odd hallucination. But the human mind is often inflamed with strange complexes. I suggest you consult your physician, Mr. Talbot."
Chick: "And take him with you, please."
Wilbur and Chick are told by the Wolfman to search the castle. They find an underground passageway and meet the Frankenstein monster. Many of the guests are hypnotized by Dracula and Wilbur is captured to be operated on by Dr. Mornay. There is a complicated chain of events that culminates in the destruction of all three monsters. Chick and Wilbur believe it's all over until they see a floating cigarette in the air. The voice of Vincent Price says, "Allow me to introduce myself. I'm the Invisible Man."
This is probably Abbott and Costello's best movie, with an inspired mixture of laughs and scares. It's an all time great horror-comedy that works well because the monsters play it straight. The film was a critical and box-office success that led to a resurgence in the comic duo's popularity. But this lively spoof was not so kind to the monsters. It is the last appearance of Universal's version of the Frankenstein monster. Bela Lugosi is terrific in his second and last screen performance as Dracula. He was buried in the cape he wears in this movie.
Others in the cast include: Charles Bradsteet (Dr. Stevens), Howard Negley (Harris), Bobby Barber (waiter), Harry Brown (photographer), and many others. The screenplay was written by Robert Lees, Frederic I. Rinaldo, and John Grant. Frank Skinner composed the music. Charles T. Barton directed.