What follows contains a huge number of spoilers for the Christie book Cards on the Table. The spoilers are necessary because I want to rant about the movie version which changed every single fucking denoument except for the vaguest stuff. I'm sorry, but if you start changing the "answers" in a Christie story you are going to lose her genius. Her beginnings lead to her answers, not to yours. If you want to write a mystery where C and D happen at the end instead of A and B, write your own mystery and don't use hers.
The plot is that a theatrical sicko invites four detectives (one private--Poirot--one police, one army, and one amateur sleuth) and four people he knows have gotten away with murder in the past to dinner. The idea is that he wants to see them get caught--if they can be caught. Like I said, a sicko. Well, predictably, after he goads them with vague conversation referencing each of their crimes in a general way, one of them takes the bull by the horns and kills him.
The four murderers are:
-Miss Meredith, who stole stuff from her employer and poisoned her to avoid getting in trouble about it
-Mrs. Lorrimer, who had killed a husband waaaay in the past
-Major Despard, who actually is not a murderer, but the sicko/victim had listened to the wrong rumors this time
-Dr. Roberts, who killed a patient called Dorothy to avoid the fact of their affair getting out.
The one who actually killed the victim of the book was Roberts. During the course of the real novel, he kills Mrs. Lorrimer and tries to make it look like a suicide intended to protect Miss Meredith (since it turns out they are mother and daughter)--thus making it first look like it was the mother who did it, then looking like it was the daughter, and not looking like it was the doctor at all.
No actual murderer goes unpunished in the novel. Lorrimer dies at Roberts' hands. Meredith dies when she tries to push her housemate (who knows everything) overboard in a canoe and they both go into the water. Major Despard, who had been courting them both sort of, rescues the housemate instead of Meredith becuase that's where his feelings truly lay, thus leaving Meredith punished by her own actions.
Roberts goes off to prison, probably to be hung or something. Or maybe in the novel he takes poison. I can't remember. Well, anyway.
In the movie, first of all:
-Mrs. Lorrimer goes unpunished, 100%
-Meredith was innocent all along and it was the housemate who had poisoned the employer (to avoid Meredith getting in trouble) and then tried to kill her to avoid either being found out or losing her to Despard? Or losing Despard to her? I can't follow it at all. I can't even figure out what they were implying.
OK, and are you ready for this??
Dr. Roberts was gay and shagging Dorothy's husband, and that's why she had to die. And then they replaced good old Superintendant Japp or Battle or whoever was the recurring character representing the police with some unknown named Wheeler, who turns out to be gay also. The purpose of that seems to be to 1. add the red herring that is not in the novel of "what if one of the detectives did it, and not one of the murderers?" and 2. make a distinction between Fags Who Kill and Fags Who Don't. "OK, we know that you're not all like that! Hee hee."
I really didn't need to hear Poirot's choice words on the subject. I know he's le bon catholique, but still. Moo.
Folks, I understand that maybe you're trying to make us feel welcome in this world, and I appreciate it since I've been the one begging for it for years. But you did it right in the other movie, the one where one of the red herring suspects was gay. Because it didn't change the solution to the mystery at all!!!! Dude. Don't. Change. Aggie's. Solutions.