You Have 48 Hours
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.
Most commonly used in cop shows, in which Da Chief will give our hero two days to close the case and find the evidence on the suspect before the DA (district attorney) throws the case out (discards or rejects). As an added incentive, he might risk losing his badge. If Da Chief is on friendly terms with the hero, he may give him the 48 hours as a favour. Another variant is that the cop needs to make something stick, as someone can only be held for 48 hours (in California; 72 hours in other states, but most writers are Californians) without being charged with a crime, after which they will presumably flee jurisdiction.
Synopsis: A single phone call can change a man's life... or possibly end it. Colin Farrell delivers a captivating, off-the-hook performance as Stu Shepard, a self-centered New York City publicist who suddenly finds himself on the deadly end of a high-powered rifle scope. Now it's a real-time race against the clock as Stu must outwit a psychotic sniper in a frantic scramble from phone booth to freedom.