Set in a late 19th century in a New England town, the film tells of unscrupulous undertaker Waldo Trumbull (Price) and his assistant, Felix Gillie (Lorre), who make a habit of re-using the coffins of the people they are supposed to bury. Also a part of the household are Trumball's old (and senile) business partner Mr. Hinchley (Karloff), who originally started the business, and the beautiful Amaryllis (Joyce Jameson), Trumbull's neglected wife and Hinchley's daughter, who has dreams (or rather delusions) of becoming a great opera singer and with whom Gillie is passionately in love.
When customers (and therefore money) begin to become scarce and money-grubbing landlord Mr. Black (Rathbone) begins demanding his unpaid rent, Trumbull and the unwilling Gillie make a nighttime visit to the home of Mr. Phipps, an elderly gentleman with a very young and attractive wife. Trumbull smothers Phipps and in the morning makes a fortuitous return so that the Hinchley and Trumbull funeral parlor will get the job of burying Mr. Phipps. However, on the day of the funeral, Trumbull discovers to his horror that Mrs. Phipps has decamped with all of the money and household furnishings ... and, incidentally, without paying Trumbull's fee.
Receiving another demand for immediate payment of rent, Trumbull and Gillie decide to murder Mr. Black, who has bouts of deathlike sleep, something that Trumbull and Gillie are unaware of.
After discovering Gillie (who had climbed into the house through an upstairs window and escaped the same way), Black seemingly dies of a heart attack but revives in the funeral parlor's cellar. After a prolonged chase and struggle to keep Black inside a coffin, Trumbull knocks Black out with a mallet to the head and places the supposedly deceased Black in his family crypt, returning home to celebrate his new-found wealth. However, Black awakes again, escapes from the coffin and crypt and returns to the funeral parlor, quoting random lines from Shakespeare's Macbeth (from which he was reciting from a script at the time of his first cataleptic attack). Humorous events follow as Black chases Trumbull and Gillie around the house with an ax before (finally) being shot and (presumably) killed by Trumbull after a lengthy monologue.
More complications arise when Amaryllis believes Gillie to be dead (he's only unconscious) and believing Trumbull to have killed both him and Black threatens to go to the police, whereupon Trumbull strangles her. Gillie comes to and seeing Amaryllis' body goes after Trumbull in revenge. The two men engage in a comical fight (Gillie with a sword and Trumbull with a poker) until Trumbull hits Gillie on the head with the poker, knocking him out, and Trumbull collapses in a depressed heap on the floor.
Gillie and Amaryllis come to at the same time and elope together. Hinchley appears and gives Trumbull some "medicine" (actually poison that Trumbull had been attempting to administer to Hinchley earlier in the film). The "medicine" works as intended and Trumbull drops dead as Hinchley makes his way back to bed, oblivious to the fact he has just committed murder.
At the end of the film, Black exhibits an allergic reaction to Cleopatra the cat, indicating that he is still alive.Vincent Price as Waldo Trumbull
Peter Lorre as Felix Gillie
Boris Karloff as Amos Hinchley
Basil Rathbone as John F. Black, Esq.
Joyce Jameson as Amaryllis Trumbull
Joe E. Brown as the Cemetery Keeper
Beverly Hills as Mrs. Phipps
Alan DeWitt as Riggs
Buddy Mason as Mr. Phipps
Douglas Williams as the Doctor
Linda Rogers as Phipps' Maid
Luree Holmes as Black's Servant
Rhubarb the cat as Cleopatra
The film was a follow-up to The Raven, meant to reunite Vincent Price, Peter Lorre and Boris Karloff. The original intention was for Karloff to play the part of the ceaselessly spry old landlord, Mr. Black, but, by the time production was set to begin, it was realized that it would have been difficult (if not impossible) for Karloff to perform the physical requirements of the role, due to persistent back and leg problems which had worsened with age. So, Karloff traded roles with Basil Rathbone, and instead played Amaryllis' elderly father, Mr. Hinchley.
There was a great deal of physicality demanded of Peter Lorre's character, Mr. Gillie. It's fairly obvious — while watching the film — that a professional stunt man was utilized for the frequently rendered tumbles and pratfalls. The stunt double, Harvey Parry, was outfitted with a full mask crafted in Lorre's likeness, complete with his instantly recognizable pop-eyes.
The movie was not a big success at the box office. Matheson:
It didn't lose any money. They [AIP] told me that the title itself cost them a lot. It's such a contradiction in terms, though. Terror sells and comedy makes them go away, so it's like they're walking in two directions at once. But I thought it was very clever to do a take off of Shakespeare's, Comedy of Errors.... I think they were probably sorry they didn't use a Poe title, because Poe had a certain marketability. I guess they couldn't figure out how to market it. But it was the last one because I was getting tired of writing about people being buried alive, so I decided to make a joke about it.
Richard Matheson wanted to write a sequel film for AIP called Sweethearts and Horrors, which was intended to star Price as a ventriloquist, Karloff as a children's TV host, Rathbone as a musical comedy star, Lorre as a magician and Tallulah Bankhead. However Comedy of Terrors was not a big hit so plans to make the followup were shelved.
A novelization of The Comedy of Terrors was written in 1964 by Elsie Lee, adapted from Richard Matheson's screenplay. It was published by Lancer Books in paperback (making certain changes in the story's ending).