Havoc is wrought on the inhabitants of a small New England town by a troubled film production. After the leading man's penchant for underage girls gets them banished from their New Hampshire location, the crew relocates to the small town of Waterford, Vermont, to finish shooting "The Old Mill".
As its title suggests, the film depends on the presence of a genuine mill, something the town is reported to possess. Unfortunately, with only days before principal photography begins, it becomes apparent that the mill in fact burned down decades ago.
Unfazed, the film's director, Walt Price (William H. Macy), places his faith in the ability of first-time screenwriter Joseph Turner White (Philip Seymour Hoffman) to alter the script. What he doesn't count on is White's apparently bottomless reserve of angst-fueled writer's block. A local bookseller, Annie Black (Rebecca Pidgeon), tries to provide White with inspiration.
The film's leading lady (Sarah Jessica Parker) refuses to do her contracted nude scene unless she's paid an additional $800,000, while a foreign cinematographer offends the locals by messing with a historic firehouse. Meanwhile, the leading man, Bob Barrenger (Alec Baldwin), dallies with Carla (Julia Stiles), a crafty local teen.
Everything comes to a head after Barrenger and Carla are injured in a car accident, which leads White (the only witness) to another emotional quandary and into the arms of Annie. Meanwhile, a powerful movie producer (David Paymer) comes to town to help Price with the ensuing mess.

Question: Why was the script altered?
Answer: The Mill they needed to shoot in Waterford Burnt down.
Alternative answer: Because the mill in the town burned down