Each guest will receive a character packet which delineates everything he/she needs to know about his/her character. Each character packet contains background information, props, confidential information (secrets, clues, etc), costume suggestions and instructions. When the party begins each guest will arrive in costume wearing a name badge with his/her character's name written on it.
No acting experience is necessary because characters can do whatever they want at the party. Some will have tasks to be accomplished (such as closing a shady deal or spreading rumors about somebody). A handful of others may be part of the entertainment (singing a song or performing magic tricks). Others may just simply choose to stand back and watch . . . gathering evidence for later accusations. There may be dancing. There may be cat-fights. There may be steamy romances, blackmailing and cunning thievery.
There will certainly be a murder.
One of the guests will know he/she is a murderer. This person will know exactly how to go about committing this murder. Another guest will know that he/she is the victim. Likewise, he/she will know exactly what to do in this role. At some point, there will be screaming and a body will be found-- perhaps a knife sticking out from the victim's chest, perhaps a rope found wrapped around the corpse's neck. Who knows?
The body will be dragged from the room, and a few minutes later a detective personality will appear, looking amazingly like the recently departed. What actually happens is the murdered victim changes costumes and becomes a detective who leads the investigation (This way the victim doesn't have to lay there for the rest of the party). The guests will be gathered, clues may be given and the rest of the party will consist of the guests trying to figure out whodunit.
The host is responsible for handing out each character packet, but he/she should also set aside a character packet for him or herself. THE PARTY RUNS SO EFFICIENTLY THAT THE HOST WILL NOT EVEN NEED TO KNOW WHO THE MURDERER OR THE VICTIM ARE! Simple directions are provided for the host on how to distribute character packets, decorating ideas and a few easy things the host will need to do before the party begins.
The party usually lasts from 2-3 hours depending on the size of the group but it can easily be shortened or lengthened depending upon your needs.