The film opens with a London gangster, Albert Spica, arriving at his posh restaurant, La Hollandais, with his entourage of thugs and a man who owes him money. While his thugs hold the man down, Albert smears dog excrement on the him and forces some into his mouth. He leaves the man behind and enters the restaurant's kitchen, where he berates and bullies some of the staff, much to the annoyance of the restaurant's manager and head chef, Richard. Albert has also brought his long-suffering wife, Georgina, with him, whom he also subjects to continual verbal abuse. Meanwhile, Albert's victim is brought into the restaurant and tended to by some of the staff.
Albert comes to the restaurant each night and holds court with his entourage and Georgina, while criticizing Richard's menu choices. Georgina notices a quiet regular customer, Michael, who is always reading. The two begin a clandestine affair with most encounters occurring in the restaurant itself. Georgina believes that if she engages in her affair in Albert's place of business, it will be easier to keep hidden from her husband.
One night, Albert becomes furious when Georgina doesn't return to dinner - she and Michael are having sex in a back room of the kitchen while Richard hides their tryst from Albert. Albert rushes into the kitchen looking for her and Richard hides them in the freezer. He returns for them a few minutes later, after Albert has left the kitchen and offers them a way to sneak out of the restaurant together; they're both hidden in the back of a truck full of rotting meat and driven to Michael's home. Once there, they are cleaned off by one of the restaurant staff and remain, hiding from Albert. However, back at the restaurant, Albert is correctly suspicious that Georgina is having an affair and, after ransacking the kitchen, vows to find the mystery lover and eat him.
One of Albert's henchmen, Cory, catches sight of a young boy, Pup, leaving the restaurant with a basket full of food (it is for the hiding lovers). Cory reports to Albert, who orders his men to capture Pup. He tortures the young boy, hospitalizing him. Georgina rushes to the hospital to visit Pup, which was a ruse to lure her away from Michael. Albert finds Michael at home and kills him by having pages of his books stuffed down his throat.
Georgina discovers that Albert has murdered Michael. She goes to Richard and asks him to cook Michael and serve his body to Albert. Richard is initially reluctant but Georgina is able to convince him, considering Albert's deplorable treatment of everyone around him, including herself and Richard.
Albert is invited to the restaurant, which announces a private party for him. When he arrives, Georgina greets him and a procession enters from the kitchen made up of everyone whom Albert has offended. The procession is carrying a long, covered tray, which is placed in front of Albert. Georgina removes the cover and Albert is horrified to see the roasted body of Michael on the tray. Albert's assistant, Mitchel, grabs a knife but is easily subdued by a few of the guests. Albert attempts to draw his pistol but is easily disarmed. The gun is passed around to a few of the guests and is finally given to Georgina, who points it at Albert and orders him to eat from Michael's body. Very reluctantly and thoroughly sickened, Albert takes a forkful of flesh and eats. After a few moments, Georgina shoots and kills Albert who falls backwards. Her last word is "Cannibal."