Lars happens across the diner and the brothers reconnect, taking refuge in the abandoned Victorian mansion on the outskirts of town that was left to them by their father, who never lived there and acquired the house through a debt. While sleeping, the two are bothered by a mouse rustling around and, when investigating, find blueprints of the house, discovering that the property was the final design of famed architect Charles Lyle LaRue, finished in 1876, and would be worth a fortune if properly restored. Ernie and Lars decide to restore the property and auction it to recover their lives. During the renovations, the two accidentally destroy the mouse's home, prompting the mouse to get even and sabotage their construction efforts. Conventional methods to get rid of the highly intelligent mouse fail as it repeatedly outwits the brothers. They resort to increasingly drastic methods to remove the mouse, including buying a psychotic monstrous Maine Coon cat named "Catzilla", whom the mouse drops down a dumbwaiter to his death, and then hiring an eccentric exterminator, Caesar, who is ultimately dragged out of the house by the mouse using his truck's winch, causing massive destruction to the floors and driving Caesar insane. Meanwhile, Ernie and Lars discover the house has an unpaid $1,200 mortgage on it they cannot pay off, since Ernie bought a $1,200 Jacuzzi tub. Because of their inability to pay the string factory's workers, the workers go on strike.