My Sinister Script

There exists a thing in the world called a 'Script'. It has no physical form, no color, no smell. But it chooses people. Those chosen will one day suddenly receive a card. On the card is only one line: 'Your script has begun.' Then, they are pulled in. Entering a completely unfamiliar horror world, playing a designated role, completing a designated task. Pass, return. Fail, die inside. No exceptions.