Majestic, which has just been launched in the US, is a game which cannot be turned off and uses artificial intelligence (AI) to involve itself in players' lives.
The scenario is similar to the film The Game, starring Michael Douglas, in which his character was entangled in a plot where he could not distinguish the game from real life.
"You only use 12% of your brain. Mind if we play with the rest?" ask Majestic's creators.
Gamers will be put in touch with other players, but will not be able to tell who is a real person and who is a character created by the computer. In one scenario a woman, who a player has been in touch with in the past, will ring them at home and plead for help, screaming that someone is trying to break down her door.
'Entertainment experience'
The contestant can then search the internet for clues, but is then sent a message telling them to back off, "if you know what is good for you".
The people behind the game are hoping that it will do for gaming what reality TV has done for television by drawing the user into the plot.
"Majestic is the first online entertainment experience," according to Neil Young, executive in charge of production at Electronic Arts, the company which developed the game.
"It is a blend of story-telling, gameplay and communications. It blurs the lines between fact and fiction to create a more compelling and engaging experience.
"Majestic is for the generation who grew up with interactivity, but grew out of playing games. It is for my generation. It is moving, powerful interactive entertainment built specifically around the strengths of the internet."
Unlike most games, Majestic chooses when the player can play and when they cannot, making the contestant move at its pace.
It has been launched in America, but the technology needed in Europe is still being developed.
Eight episodes
The conspiracy theory will involve a game company whose new product appears to interfere with the agenda of a shadowy, high-powered political organisation.
It will be split up into episodes like a TV series, with each episode taking up to a month to complete and eight inter-related episodes per series. Players can choose to play alone or in teams.
It is one of the newest titles that uses AI to learn about players' gaming styles and tailor stories and interaction to suit them.
Other new games are also using AI to enhance the gaming experience, such as Black and White, in which the player takes on the role of a God of a virgin world and must convince the inhabitants of the world's villages to worship them.
For programmers, using AI a can be a cheap way of adding playability. Instead of spending huge sums on graphics, levels, characters and plots, a game can be made more challenging with a bit of inventive programming.