One of the standard storytelling techniques is the Race Against the Clock. By giving your heroes a limited period of time to accomplish something, you immediately add an element of urgency to their story. Clocks come in all forms and lengths, but one of the most popular is the 48 hour limit, since it gives the story a deadline that's reasonably urgent but not too restrictive. It also allows for scenes set both in the daytime and at night, maximising the storytelling possibilities. Compare Stalked by the Bell, the video game equivalent. Examples of You Have 48 Hours include: