Sheila Greene, Hollywood gossip columnist, angrily stalks out of her Malibu home during a cocktail party one evening, and is struck and killed in the street by a motorist.
Cut forward one year. Her husband, wealthy movie producer Clinton Greene (James Coburn) hosts some of his movie acquaintances on his yacht for a Mediterranean cruise. The guests are all people who were at the party the night of Sheila's death. They include:
- Once famous, now washed-up film director Philip Dexter (James Mason).
- Hollywood super-agent Christine (Dyan Cannon).
- Frustrated screenwriter Tom Parkman (Richard Benjamin) and his independently wealthy wife Lee (Joan Hackett).
- Glamorous actress Alice Wood (Raquel Welch), and her would-be movie producer husband Anthony (a startlingly young Ian McShane).
Clinton offers up to all these movie hangers-on and rejects a part in his new film, The Last of Sheila, about his late wife. Because Clinton is an arrogant jerk, he doesn't just offer them jobs or anything. No, he arranges an elaborate scavenger hunt in which each of his guests are given cards with true-life secrets of a different guest. Whoever wins the game, by discovering the most embarrassing secrets about the other guests, will get to work in the movie.
However, a shocking, tragic event interrupts the second scavenger hunt. As the guests wonder what to do next, they show each other the "secret" cards and discover that one of the secrets is "You are a Hit-And-Run Killer." Tom figures out Clinton's true intention—the whole scavenger hunt routine is actually a clever ruse to expose the identity of the person who killed Clinton's wife.
The Last of Sheila was written by the oddball duo of Anthony Perkins, best known as playing Norman Bates in Psycho, and Stephen Sondheim, world-famous as the creator of Broadway musicals like Into the Woods. It is the only screenwriting credit either Perkins or Sondheim ever received.
- The '70s: This movie is very '70s. How '70s is this movie, you ask? One of the five secrets that are thought to be no big deal, definitely not worth killing over, is child molester. Another of the five secrets is 'informant' — not for turning someone into the police, but for giving names to the House Committee of Internal Security — formerly known as the Un-American Activities Committee. note
- The Alcoholic: Lee — not really Lady Drunk as she's not old and sad and bitter, she just drinks way too much.
- Amateur Sleuth: Phillip and Tom both do a decent job during their respective summations. However, Tom is faking his and Phillip also tried to kill Clinton himself.
- Asshole Victim: Clinton's appalling behavior might be justified if it was just an act to catch the killer of a woman he truly grieved for. However, it wasn't, proving that he was just a Jerkass all along.
- The Atoner: Christine admits that she informed on other Hollywood professionals during the Red Scare and now that it's over she does her best to get them work to make up for that. However, she says there are still people who, if they see her on the street, will cross the road to avoid her.
- Bath Suicide: Lee is found in the tub, having slit her wrists right after she confesses to killing Sheila and Clinton. Eventually subverted when we find out that she didn't actually kill herself.
- Bathos: In the climax, Phillip gives Tom a rundown on how Phillip worked out that Tom was the mastermind behind Clinton and Lee's deaths. The tension mounts as he tries to discreetly either summon help (unsuccessfully) or find a way out of the main saloon (also unsuccessfully). Tom then approaches Phillip with deathly intent in his eyes, whips out his hands from behind his back... which are wearing the hand puppets that Anthony was wearing earlier. Tom apologetically mutters that he 'didn't bring gloves', and then proceeds to strange Phillip.
- Blowing Smoke Rings: Clinton does this in one scene as he savors the prank he's pulling on his guests.
- The Cameo: Yvonne Romain, an actress from Hammer Horror films, appears briefly as Sheila.
- Celebrity Paradox: The TV in the room where Clinton is waiting for his guests is playing 20,000 Leagues Under the Sea, which stars James Mason, the actor who plays Phillip.
- Chekhov's Gun: The photo Clinton takes of his guests before they set sail (as seen in the page image). Also, the actual name of the movie itself! The 'last of Sheila', taken literally, is the letter 'A', which is the card that Tom swapped out to make his spontaneous plot work, and later gives Phillip the clue he needs to work out the real story. In addition, the hand puppets that Anthony plays with early in the film come back at the climax when Tom tries to strangle Phillip with them, as does the intercom that Clinton uses to eavesdrop on his guests, through which Alice is alerted to Tom's attempt to strangle Phillip.
- Chekhov's Skill: Tom's uncanny ability to mimic Clinton's voice, seen in one idle conversation, turns out to be crucial to the solution.
- Cigarette of Anxiety: Lee has to sit down and have a smoke right after she kills Clinton in a fit of rage.
- Convenient Photograph: Invoked in the photograph that Clinton takes of his guests before they set sail, which is set up by Clinton to clue them in on the solution to his game.
- Cruel Mercy: After Tom is revealed to be the killer and his attempt to murder Phillip is thwarted, Phillip decides not to turn him over to the police... in return for Tom being forced to finance the production of The Last of Sheila (with the money he obtained by killing Lee), but being creatively relegated to script "rewrites" (which he loathes doing).
- Crusading Widower: Subverted! In the end, Clinton's game was related to Sheila's fate only in the most tangential way — one which leaves the viewer in doubt about whether he even really cared about her death at all.
- Development Hell: In-Universe, this is the hold Clinton has over Tom Parkman; Clinton bought the option to one of Tom's screenplays but has no interest in actually making the script into a film.
- Fair-Play Whodunnit: Loaded throughout with clues that might help a viewer solve the mystery, like the group photo taken early in the story, or Tom's Chekhov's Skill, or the ice pick that one character is seen using right before another character can't find it.
- Fanservice: Alice and Christine spend a goodly chunk of the movie lounging around the yacht in their bikinis.
- Fate Worse than Death: By being forced to finance the production of the In-Universe film The Last of Sheila (with the money he would otherwise have had for himself), but being creatively relegated to script "rewrites" (which he loathes doing), Tom is consigned to a personal hell worse than if he'd been turned over to the police.
- Freeze-Frame Bonus: When the slips of paper are handed out and given milliseconds of screen time, one says "Alcoholic" which doesn't reappear until the end, providing an early hint that one of the secrets is fake.
- Group Picture Ending: The film ends with a Call-Back shot of the snapshot Clinton took of his six guests.
- Halfway Plot Switch: Starts out as a comedy about a complex Scavenger Hunt-type game, then turns into a murder mystery.
- Hand Puppet: Anthony the weirdo brings his hand puppets on the trip. Later, Tom tries to use them to strangle Phillip, muttering "I don't have any gloves."
- Horrible Hollywood: The main characters are all either selfish, ladder-climbing venal Hollywood types or selfish, successful venal Hollywood types. The film ends with two people deciding to let a double murderer go free as long as they can get a movie produced as part of the deal.
- Internal Reveal: The audience finds out about the secrets actually being real facts about the players, and the existence of the "hit-and-run killer" card, before all the characters become aware of those things.
- Irony: The ending of the movie proves just what rotten friends these people are to each other. The final shot and ending credits are set to Bette Midler's song "(You've got to have) Friends".
- Jerkass: Clinton, who delights in embarrassing and humiliating his guests as he dangles the prospect of work in front of them. Honestly, it's a little surprising that no one murdered him sooner, given that this is noted to be typical of his behavior.
- Jerk with a Heart of Gold: Tony is blunt, and sometimes mean-spirited, but he doesn't hesitate to dive into the water to save Christine from the propeller and out of everyone there, he is the only one who isn't having an affair, plotting a murder or willing to cover up a murder.
- The Last Title: The Last of Sheila.
- Leaning on the Fourth Wall: A lot of this, as the characters are all movie people who call out the story beats as if they're in a movie. When they reach the abandoned monastery, they compliment the set design. When Phillip is explaining how the whole mystery went down, he says "Dissolve", and the scene dissolves to the next scene.
- Mistaken for Prostitute: As Christine is walking around town during the first scavenger hunt, holding a key to an unknown room, she keeps getting approached by johns thinking she's a Streetwalker offering the key to her room.
- Ms. Fanservice: Christine wears bikinis for a large amount of her screen time and has a good body for it.
- Necro Cam: Used when Phillip explains the extremely complicated murder solution to Tom.
- No Celebrities Were Harmed: One of the gags was how all the characters are modeled after real people. Philip Dexter, the once-great director now reduced to appearing in commercials, is Orson Welles. Christine is actually Real Life agent Sue Mengers, who passed on playing an Expy of herself and gave the role to her client, Dyan Cannon. Tom Parkman is actually Anthony Perkins himself, a closeted gay man married to a woman, whose career had stalled (Perkins's career had stalled due to typecasting after Psycho). Alice and Anthony Wood are actually based on Raquel Welch and her then-husband, producer Patrick Curtis. (Sondheim got Welch to play the part by lying and telling her that Alice and Anthony were based on Ann-Margaret and her husband.)
- Ominous Latin Chanting: Clinton arranges some cassette players to play Gregorian chants as the scavengers root through the monastery.
- Plot Twist: Several zig-zags in the story: Clinton's cruise is actually a ruse to expose the killer of Sheila, Clinton ends up getting murdered, Lee confesses to killing both Sheila and Clinton and commits suicide, Philip figures out that Tom actually murdered Clinton and Lee (and that Clinton wasn't behind the ruse to expose Sheila's killer).
- Posthumous Character: One of the most striking things about the film is the extent to which this trope is downplayed. In the end, no one of Sheila's friends seems to be interested in Sheila as a person and a character — only as a potential source of revenue from the adaptation. Not even her husband, who, as it turns out in the end, likely never intended to investigate into her death.
- Red Herring:
- The whole incident in which someone turns on the engine, nearly killing Christine as she swims. It turns out to be Phillip, who was trying to kill Clinton (also out swimming), but it's not related to the main mystery.
- Sheila suddenly leaving the party on the night of her death (most probably she just got mad at Clinton).
- The Reveal: Several! Tom killed both Clinton and Lee. Clinton's game wasn't about his wife's death at all, it was just him screwing with his guests because he's a Jerkass. Lee's secret wasn't "Hit-and-run killer", even though she actually was the hit-and-run driver who killed Sheila, it was "Alcoholic". Tom changed the cards when he whipped up a spur-of-the-moment plan to kill Clinton and Lee, thus allowing him to make the script he sold to Clinton, with Lee's money.
- Scavenger Hunt: A particularly elaborate one with a series of clues.
- Shout-Out: Clinton (James Coburn) mockingly refers to Tom's latest film as "A Fistful of Lasagne". This is obviously a jab at the Spaghetti Western genre, namely, such films by Sergio Leone as the pioneer A Fistful of Dollars and A Fistful of Dynamite. The latter one, shot two years before The Last of Sheila, featured Coburn himself in a leading role.
- Spotting the Thread: Phillip is not satisfied with the tidy solution. He ponders the card that says "Little Child Molester", with the odd redundancy of "little". He realizes that the card secrets — "shoplifter", "homosexual", "ex-convict", "informer", "little child molester", and "hit-and-run killer" — are actually an acrostic that is supposed to spell out "SHEILA". The only problem is that they spell out "SHEILH" because there's no card that starts with A. Phillip realizes that "hit-and-run killer" doesn't fit... and that was Tom's card. Then he remembers Tom crumpled up his card, but the "hit-and-run killer" card is uncrumpled. He unravels the whole mystery from there.
- Thousand-Yard Stare: The second-to-last shot of the film is of Tom staring blankly into the camera, completely broken thanks to the Cruel Mercy that Phillip has subjected him to.
- Title Drop: Clinton wants to make a movie called The Last of Sheila. This doubles as Foreshadowing when Phillip later realizes that the movie title is a vital clue.
- Voice Changeling: Tom's really good at imitating people. That's important.
- Where Everybody Knows Your Flame: As Christine wanders around a seaside town trying to solve the first scavenger hunt, she stumbles into a lesbian bar. A bunch of butch lesbians gape at her before she beats a hasty retreat.
- Xanatos Speed Chess: That's a pretty elaborate plan that Tom came up with on the fly, once he was aboard Clinton's yacht and discovered the nature of the scavenger hunt.