I'm trying to write a Christmas related murder whodunit play. But I have no idea what the plot should be about. Since it is a play, there cannot be too many different settings and I cannot have too many characters. Your suggestions are greatly appreciated.
Well you can always go for the poison option. I guess you could always go for spiking the eggnog with arsenic, cyanide or something like that. Just how many people do you want to die? Is this just a one or two person murder, A mass murder all at once, Or a mass murder that happens over the course of the story person by person?
There are plenty of ways to commit the murder without it being a "gusher". Poison, blunt object, suffocation, strangulation, electrocution, gunshot (doesn't HAVE to be super messy, especially with a small calibre handgun) stabbing with a kabob skewer or a knitting needle, drowning... The PLOT would derive from a conflict and a goal. The primary plot is simple. The goal is to solve the murder. The conflict arises frome the murderer not wanting to be caught. Additional plots would arise because various characters would have secrets to conceal, while your investigator(s) will wish to uncover secrets in the search for the killer. What will make or break your mystery will undoubtedly be the characters themselves. Also, decide what the tone of the play will be. Is it suspenseful and dark, or is it a comedy. That will help you decide what to do with your characters, full of angst and rage, or exaggerated and quirky/eccentric.
Murderer: serial killer disguised as Santa Claus. Modus operandi: electrocution with Christmas tree lights.
How about trying this plot: A childish teenager was sleeping that Christmas night. As the teenager hasn't outgrown his childish ways, he leaves his stocking by the fireplace and waits for Santa Claus. But as soon as his head hits his pillow, he falls into deep sleep. Someone slinking in the dark shadows come toward him. That someone has a family feud/personal grudge with the teenager. That someone tiptoes towards him and injects something in the teenager's arm. That something can be something harmful like poison, etc. Well, I don't think that it's a very good idea but no harm trying it, right? Failing is the route to success.
How about: A family goes camping for Christmas in a far away cabin in the woods. Some of the family hasn't got together in years .Others want no part in their family. But all of them have dark, mysterious past that are not yet revealed. Then, one by one, the family falls prey to an unknown murderer. Little by little their pasts are uncovered. Each history makes the reader believe that that character is the murderer. Then you read a chunk of the next person's past. No, that person must be the murderer....Until they all die and the murderer is revealed. ...I'm not much of a horror writer.