art Hughes has a pretty good life, a beautiful wife, a young son, a good job with promotion prospects, and a renovated brownstone in New York. When wife and kid leave for a vacation, Bart stays behind to work on a project that will earn him that promotion, unaware that a certain inhabitant of his basement has other plans for his time. Bart goes a bit bonkers trying to kill this rat, destroying most of his house in the process. Certain allegorical elements tie the household conflict to the "rat race" in his office, but the main event is certainly the night-and-day contest of wills between man and rodent.

Overview from themoviedb.org