While Donald's nephews are in a Junior Woodchucks camping, Donald spends time in his secret hideout. When he tests his amplifier earplugs, hears twin intruders from the backyard who go to his room. Instead of going there, Donald keeps hearing to know what do they plan, and hears they wanted to use an obedience serum on him. After the twins leave, Donald goes to see Gyro Gearloose.
Gyro tells he created the serum for two clients who were twins, and there's also an antidote pill. Donald eats the pill and explains Gyro that the twins seemingly want to use the serum on him. Gyro assures him that he's immunized now and also gives him a needle with more serum and a letter envelope.
Donald finds the twins, Tim and Tom, awaiting him at home, they inject him the serum and he pretends to be under their control. The twins want Donald to get into Scrooge McDuck's house and get the statue of Pollux. The twin Tim sends Donald to sleep to commit the tefth tomorrow, and locks the door from the outside. Donald takes the chance to use his secret elevator and become the Duck Avenger. When Tim goes after Donald, doesn't manage to notice it's a decoy until the Avenger ambushes him and treathens him into accepting to be injected with the serum. The Duck Avenger orders him to knock Tom out and tie him.
The Duck Avenger asks the controlled Tim who is their boss, but Tim only knows him as Mister Mistery and has never seen him. However, he knows where to find him at midnight to give him the statue. The Duck Avenger decides to steal the statue to catch Mr Mistery.
The Duck Avenger enters Scrooge's house by the window to Scrooge's office, where the old glaswegian is alongside the Pollux statue. The Avenger tells Scrooge that Donald sent him to help, and Scrooge explains he got the statue for ten cents in a poll, but since two robbery attempts he deduced it should be valuable. As the mythological Pollux had a twin named Castor, the ducks deduce the twin statues must be reunited to be actually valuable, and the Avenger guesses Mr Mistery must have the Castor statue. However, Scrooge doesn't trust the Avenger and treathens him with a rifle. The Avenger hands him Gyro's envelope pretending it's a letter with the secret of the statues, but it contains sleeping gas that gets Scrooge asleep while the Duck Avenger takes the statue.
The controlled Tim guides the Duck Avenger to the meeting place with Mr Mistery. While Tim doesn't see Mr Mistery's face when handing him the statue, the Avenger manages to tie a bottle to his car, and it spills a bright liquid that allows them to follow the villain. A sudden rain cleans the liquid, but the Duck Avenger finds recent traces of tires guiding them to John D. Rockerduck's house. The Avenger uses his electronic key to open the door and finds Rockerduck with both statues. Rockerduck explains he bought cheap the Castor statue in a bazaar in Athens, and he knew the statues would have a bigger value together. The Duck Avenger notices Castor lacks an eye, so breaks Pollux and finds in it Castor's missing eye, reattaches it and the statue base reveals a treasure map. Then the Avenger punctures Rockerduck with a normal needle pretending it's the obedience serum. The suggestioned Rockerduck is told to pretend to be a monkey and eat his hat as if it was a banana.
The Duck Avenger returns home alongside Tim and has him kicking Tom all the way of the twins' return to their house. He becomes Donald again and calls uncle Scrooge to tell him the Duck Avenger gave him something valuable. Scrooge arrives to find it's the map for King Minos' treasure. Donald wants to go sleep in his room, but Scrooge drags him along to search the treasure.