A leprechaun wants its gold back.
O'Grady returns home in a limousine from the funeral of his mother in Ireland and is greeted by Mrs. O'Grady. He tells her they are leaving tomorrow to look at mansions. He gives the limo driver Joseph a hundred dollar tip and then opens a package he mailed home from Ireland. He breaks open an urn and pulls out a bag of gold coins. Mrs. O'Grady hears a voice and walks into the living room and finds a locked suitcase. She unlocks it and the Leprechaun climbs out. Mrs. O'Grady in shock, falls down the basement stairs and breaks her neck. O'Grady grabs a gun and a four leaf clover and manages to lock the Leprechaun inside of a wooden crate which he hammers shut and leaves the four leaf clover on top of. As O'Grady is about to burn his house down, he has a stroke and collapses.
10 years later, Tory and J.D. drive to J.D.'s new house in North Dakota. While walking through the house she sees a tarantula and tells J.D. she is leaving to stay in a hotel. While talking on her cell phone, she bumps into Nathan who is there to paint the house. After Nathan laughs at Tory for being afraid of spiders, she decides to stay to prove to him that women are not always afraid and run away. Ozzie tells Alex he saw a flying saucer and Alex criticizes him for lying. While bringing a drink to Nathan, he accidentally drops a tarp on Tory and she drops the drinks on the crate holding the Leprechaun. As they are about to open the crate, they hear Ozzie scream outside and find him covered in paint. After cleaning himself up in the bathroom, Ozzie hears a voice and goes into the basement and knocks the four leaf clover off the crate, releasing the Leprechaun. The Leprechaun threatens Ozzie and demands to know where his gold is and Ozzie runs away. Ozzie runs outside and tells everyone that he saw a Leprechaun, but no one believes him. They all go into the basement, but only find what appears to be a rat, but is the Leprechaun in disguise. As they go outside Ozzie sees a rainbow and he runs away to find the end of it and Alex follows after him. At the end of the rainbow, Ozzie and Alex find the Leprechaun's bag of gold and Ozzie swallows a coin trying to figure out if it is real. They promise not to tell anyone about it and Alex takes one coin to have it checked out in town after they hide the gold in the well. As Tory is getting a can of paint, the Leprechaun scratches her leg. She screams and J.D. and Nathan run to her. They hear a meow and J.D. thinks it was a cat that scratched her and sticks his arm into a tree stub to try and catch the cat to see if it had rabies. The Leprechaun bites J.D. in the hand and Tory, Nathan, Alex and Ozzie get into Nathan's truck to take J.D. to the hospital.
When they get to the hospital, Nathan tells Alex and Ozzie that he and Tory will meet them at the cafe later. Alex and Ozzie go to Shop Owner's collectibles store and Alex shows him the coin. The Shop Owner asks to keep the coin overnight to study it and then Alex and Ozzie leave. The Leprechaun enters the store and takes back his gold coin after biting the Shop Owner in the leg. He then kills the Shop Owner by repeatedly jumping on his chest with a Pogo stick. As the Leprechaun is driving a toy electric car he stole from Show Owner's shop, he is stopped by Deputy Tripet. The Leprechaun attacks Deputy Tripet, who runs off into the woods with the Leprechaun chasing after him. The Leprechaun eventually catches Deputy Tripet and kills him by snapping his neck. Alex and Ozzie meet Tory and Nathan at the cafe, while the Leprechaun goes back to the O'Grady house to look for his gold. He then piles up a bunch of shoes and polishes them. Tory, Nathan, Alex and Ozzie return to the house and find the house a mess. Nathan goes outside when he hears a bicycle bell and gets his leg caught in a bear trap. The Leprechaun attacks Nathan, and Tory, Alex and Ozzie run outside. Tory and Alex help fight off the Leprechaun while Ozzie calls the sheriff's department. He tells the Dispatcher that the O'Grady farm is being attacked by a Leprechaun. The Dispatcher hangs up with Ozzie and laughs and tells Sheriff Cronin that Ozzie called about a Leprechaun attack. Alex brings Nathan a shotgun and he shoots the Leprechaun. Tory and Ozzie carry Nathan to his truck and they and Alex try to leave, but when Alex goes to open the hood to mess with the distributor cap, the Leprechaun jumps out at him. The Leprechaun bites Ozzie in the ear, but runs off after Tory burns him with a cigarette lighter. The Leprechaun then jumps into the toy electric car and rams the truck, causing it to flip. Tory, Nathan, Alex and Ozzie run back into the house and shut the door. Tory calls the police on her cell phone. Sheriff Cronin contacts Deputy Tripet, and the Leprechaun mimics Deputy Tripet's voice and tells Sheriff Cronin he will check out the O'Grady farm. Ozzie while arguing with Tory about if it is a Leprechaun attacking them accidentally mentions the gold. Alex tells Tory where he and Ozzie hid the gold and she pulls the bag of gold from the well and gives it back to the Leprechaun.
The Leprechaun counts his gold and realizes a coin is missing. He then jumps from the fridge and attacks Alex before running off. Ozzie tells Nathan and Tory that he has his last coin in his stomach. Tory then decides to go into town to ask O'Grady, who is now in a rest home how to kill the Leprechaun. Tory takes her jeep into town while Nathan and Ozzie distract the Leprechaun by throwing shoes at him. She drives to the Chillview Center and sneaks by security guard Henderson to O'Grady's room. She goes into O'Grady's room, but the Leprechaun is already there and she runs into an elevator where a dying O'Grady tells her she needs to use a four leaf clover to kill the Leprechaun. Tory returns to the house and she looks for a four leaf clover in a clover patch, before she is run off by the Leprechaun. She runs away and finds Deputy Tripet dead, and is saved by Nathan who shoots the Leprechaun once more. Tory, Nathan and Ozzie search the clover patch for a four leaf clover. After saying she believes, Tory finds one. The Leprechaun attacks Alex in the barn and Ozzie tells the Leprechaun that the last coin is in his stomach and runs away. Alex runs after Ozzie and the Leprechaun after grabbing the four leaf clover from Tory and uses his slingshot and gum to shoot the four leaf clover into the Leprechaun's mouth before he can kill Ozzie. The Leprechaun starts to dissolve and falls into the well. Nathan then pours gasoline into the well and drops a match down into it, causing a large fire ball to erupt. J.D. and a group of sheriff deputies then arrive and the Leprechaun vows vengeance.