Submitted by Tornado Dragon
While Lars and Ernie are having a heated argument, Lars throws an orange at Ernie, but Ernie dodges it and it randomly strikes the mouse, who was behind Ernie watching the fight. The hit leaves the mouse stunned, and when neither of the brothers can bring themselves to kill it, they put it in a box and mail it to Fidel Castro. Though the brothers are able to finally finish their renovations on the house in time for the auction, the box soon gets sent back to them by the Cuban post office due to insufficient postage (since Lars didn’t get the box weighed).
Just before the auction starts, Lars finds the box sitting outside with a hole chewed through it, and when he tries to tell Ernie about it as he is kicking off the auction, Ernie spots the mouse come up through the podium he is standing at and eat his father’s lucky piece of string that he had set down on it. As the auction goes on, the brothers once again try to kill the mouse, and they end up sticking a garden hose in the wall intending to flood the walls with water and flush him out. However, Lars turns the spigot so hard that it breaks off, causing gallons of water to fill the inner walls, and eventually, the water busts through the wall behind the auctioneer. This causes Lars, Ernie, and all of the guests to get washed outside, and then the entire house collapses. The guests promptly leave (including Lars’ gold-digging wife April, who leaves with one of the bidders), and the brothers spot the lucky string float down from above and land in front of them, and they come to think that the house’s destruction finally killed the mouse. However, as they drive away from the property, we see the mouse riding underneath their car.
Lars and Ernie head to their string factory, where they drink wine and eat bread and cheese in the office until they fall asleep. Taking pity on them, the mouse takes the hunk of cheese that they were eating, starts up the machinery, and puts it into the wax-fiber boiler, resulting in a ball of string cheese getting created. Having been awoken by the machinery, the brothers see the string cheese ball, and after Ernie tries a piece of it, they spot the mouse nearby looking at them and realize that he made this. Sensing a real business opportunity, the brothers make peace with the mouse, then renovate and retrofit the factory to facilitate the manufacturing of cheese-based products. Lars runs the factory and starts dating Hilde, a Belgian hair model he earlier got acquainted with, and Ernie becomes the head chef while the mouse becomes the quality control officer, taste-testing the various flavored cheeses that Ernie makes before they hit the market.
One day, a banker pays Lars (Lee Evans) and Ernie (Nathan Lane) a visit at the antique house, and he informs them that the $1200 that Ernie borrowed against the house towards the cost of renovations is overdue, and the bank will foreclose on the place if they are not reimbursed in two days. After thinking about how they can get the money, they take a drive to their string factory, with Lars explaining that he is going to tell the workers that they are going to have to forfeit their next couple of paychecks so he and Ernie can pay off this new mortgage, figuring that they will be able to give them their money later once they auction off the house. As Ernie sits in the office, Lars explains to the workers that he and his brother are flat broke before telling them of what will become of their next couple of paychecks, and this is – unsurprisingly – met with condemnation from the workers. Meanwhile, Ernie randomly finds an acquisitions contract from Zeppco International, a successful cord company, lying on Lars’ desk (two business representatives from Zeppco met with Lars earlier in the film and offered to buy the factory from him, but Lars refused to sell it because he promised his father Rudolf [William Hickey] on his deathbed that he would never do that, and they left him the contract if he ever decided to change his mind), and after noticing that they are offering a $100,000 advance upon receipt of a signed contract, Ernie decides to meet with Zeppco in secret and accept their buyout. Lars comes into the office fleeing from the workers, and as he tells Ernie that they are going to have the find the money somewhere else, he and Ernie escape out a window and drive back to the house.
After hiring an exterminator, Caesar (Christopher Walken), the next day and leaving him at the house to get rid of the troublesome mouse, Lars and Ernie head back to the factory. As they avoid the striking workers, Ernie sends Lars inside to try to make $1200 worth of string by himself so they can meet their customers’ orders, and he tells Lars that he can’t help him because he needs to “run an errand”. Lars’ efforts end disastrously when he gets his clothes caught in some of the machines, causing him to get stripped down to just his shoes and socks. Meanwhile, Ernie calls the number on the business card that Zeppco left with the contract and gets a hold of Vinny, one of the business representatives that Lars had met with, and he tells Vinny that he is willing to discuss selling the string factory to Zeppco and that he will meet him at Ellman Square under the big clock at noon. While Ernie is waiting, he gets the attention of two Belgian hair models, Ingrid (Debra Christofferson) and Hilde (Camilla Søeberg), sitting on a bench across from him, but just as he attempts to go over and introduce himself to them, his hat blows away in the wind. As he runs to retrieve it, Vinny and another representative arrive in the square. Ernie reclaims his hat in the street, but just after he notices the reps and tries to get their attention, he suddenly gets hit by a bus and is then taken to the hospital.
We then see Lars’ and Ernie’s lawyer (Eric Christmas) stopping by Lars’ house to discuss preparations for the auction with him, but Lars’ estranged money-hungry wife April (Vicki Lewis) answers the door instead. After he tells her why he is here and then says (off-screen) that the house could be sold for millions, she heads over to the string factory and reconciles with Lars. Lars then receives word about what happened to Ernie and goes to the hospital to see him, and after he meets Ingrid and Hilde when he gets there (who came in the ambulance with Ernie out of concern for his well-being and also so they could give him back his hat), he tells Ernie that April is going to give them the $1200. As for Caesar, the mouse gets the better of him by attaching the cable of his borescope to his truck’s winch line and hitting the switch, and since this is attached to his equipment pack, he is dragged right out of the mansion and causes extensive damage to the floors, stairs, and plumbing as he goes. The mouse then somehow manages to lock him in a trunk in the attic.
As Lars and Ernie are driving back to the antique house, Ernie asks Lars if April gave him the money because she had heard about the auction, and he replies that he never told April about it until after she took him back. Ernie remarks that things are looking up for them now and Lars will be able to keep the factory, and Lars starts to tell him that there is something pertaining to the factory that he should have mentioned before, after which Ernie says that he has something to confess as well. However, before either of them can say what they have to say, they notice Caesar’s truck being towed away, and when they arrive at the house, they find that the cops and paramedics are there and a traumatized Caesar is being loaded into an ambulance. They then go inside and see the aftermath of the destruction that was just done, and they soon encounter the mouse and try to kill it themselves once again, but all that results is more damage being done to the house as well as them. Shortly afterwards, the phone rings, but the call goes to the answering machine since neither Lars nor Ernie are able to answer it quickly enough, and the caller turns out to be Vinny. The brothers listen as Vinny says that he and his partner waited in the square for Ernie for over an hour before giving up and leaving, and he adds that, because they don’t like being treated this way, especially since Lars already turned down their offer, they have decided to take their proposal off the table. This causes Lars and Ernie to have a serious argument that devolves into both of them declaring that they hate each other, after which they each look around for something to throw at the other. Lars eventually picks up an orange and chucks it at Ernie, but Ernie gets out of the way, and the orange strikes the mouse, who was right behind him watching the fight. They check on the mouse and see that the blow has just stunned him, but neither of them find that they have the guts to finish him off. Therefore, they decide to just seal the mouse up in a box and mail him to Fidel Castro. Afterwards, the brothers patch up their differences and get the mortgage paid off with April’s help, and around the time they finally get their renovations completed, the box arrives at a Cuban post office. However, the workers immediately send the box back to the house due to insufficient postage (since Lars didn’t bother to have the box weighed before it was sent).
At the auction, Lars gives Ernie their father’s lucky piece of string, explaining that their father meant for them to share it. Ingrid and Hilde then show up as invited guests of the brothers, and Hilde gets to talking with Lars, where she shows a sincere interest in visiting his string factory. Shortly afterwards, Lars is alerted to the return of the mouse when he finds the box sitting outside with a hole chewed through one of the corners, and when he comes back inside, he catches his and Ernie’s lawyer greeting April (who also decided to attend) by name and remarks how nice it is to see her again, making him realize that she DID know about the auction before he told her and she is only back with him because she thinks that he is going to become rich again. Just as Ernie is officially kicking off the auction in one of the rooms, Lars unsuccessfully tries to warn him through hand gestures from the back of the room about the return of the box, but Ernie finds out about the rodent’s return for himself when it suddenly crawls up through the hole for the podium’s microphone stand and eats the lucky string, which he had set down in front of him. After he unsuccessfully tries to kill the rodent with the auctioneer’s gavel, he decides to let the auction proceed, but he instructs the auctioneer to keep it going no matter what happens.
He then meets up with Lars, and after each informs the other about the mouse’s return and Ernie tells Lars that it ate their father’s lucky string, they start trying to catch the pest once more. Their efforts cause nothing but disruption and chaos, and Lars soon brings in the garden hose from outside, which he and Ernie stick into a hole in the wall that the mouse just escaped into. Ernie orders Lars to turn the water on full blast so they can flush out the mouse, but Lars turns the spigot so hard that it breaks off. This causes gallons of water to flood the inner walls, and just as the mansion is about to be sold, the wall behind the auctioneer bursts, causing an enormous amount of water to come out and wash Lars, Ernie, and all of the guests outside. Moments later, the entire house collapses to the ground. The bidders promptly leave, and April decides to officially ditch Lars for one of them. As the brothers stand on the ruins of the house, Rudolf’s lucky string floats down from above and lands in front of them, and they draw the conclusion that the house’s destruction must have finally killed the mouse. They drive away from the property soon after, completely unaware that the rodent is still alive and is now underneath their car, hanging on to the exhaust pipe.
Ernie and Lars drive to the string factory and drink wine and eat cheese and bread in the office until they fall asleep. However, they are awoken by the sound of the factory’s machinery operating, and they notice the hunk of cheese that they were eating being put into the wax-fiber boiler. This causes a ball of string cheese to get created, and after Ernie tries a piece of it, he and Lars look up and spot the mouse sitting atop one of the machines, and they realize that the mouse made this, having decided to take pity on them (though it has been theorized by viewers that the mouse is actually a reincarnation of Rudolf himself). Sensing a real business opportunity, the brothers decide to make peace with the mouse, then they renovate and retrofit the entire factory to facilitate the manufacturing of cheese-based products. Lars runs the factory and starts dating Hilde, and Ernie becomes the head chef while the mouse becomes the quality control officer, taste-testing the various uniquely-flavored cheeses that Ernie makes before they hit the market.