After Vicky gets fired for erasing a videotape that the Turners were saving so that they could use it to get their own reality show, she decides to take over Dimmsdale and wage war on Earth. Timmy must now stop her and never return her to babysitting at all costs for life! Unfortunately, every time Timmy wishes she was not the supreme ruler of something, she becomes a supreme ruler of a very most powerful position.
Timmy's parents plan on attending a cinema, leaving Timmy once again, alone with Vicky. But this, time Timmy plans on exposing Vicky as the mean babysitter that she is. He has his fairies poof his parents back to the living room where they view videos of Vicky torturing Timmy in a dungeon or swirly. However, Mr. and Mrs. Turner don't even bat an eye at the incriminating evidence and couldn't care less. Luckily, Timmy had anticipated this and made sure that Vicky taped over his parents' home movie video, which Mrs. Turner briefly instructed Timmy not to mess with, and was playing right in front of them. The Turners finally realize the truth at last, just as Vicky comes in with two electrical saws. At Timmy's request, they fire Vicky, then decide that Timmy is old enough to take care of himself.
Determined to get a job (because for some totally inexplicable reason, being fired by Timmy's parents means she can no longer babysit other kids), Vicky goes all over Dimmsdale, but the best she can do in each job is torture people, resulting in her getting shunned by all her bosses, both literally and figuratively. Eventually, she goes to the mayor and reveals to Chompy the Goat that the mayor indulges himself in eating goat meat, causing the goat to chase him out of his office. Vicky then names herself the new mayor and takes over Dimmsdale, with the help of her newly established ape army, renaming it Vickyland. Timmy, who is enjoying the time of his life with his godfamily, staying at home while his butler Jensen does his grades at school, soon discovers that getting Vicky out of his life causes her to ruin everyone else's. Wanda proposes that they take fire-breathing battle-rhinos and a lion-cloth warrior to Vicky to depose her; however, they lose badly, and Timmy tries wishing that Vicky wasn't the mayor. Unfortunately, Vicky somehow becomes President of the U.S.A. Timmy tries unwishing again, only for Vicky to become a supreme galactic warlord and began attacking Earth with her Star-Destroyer-like warship. To save the Earth, Timmy reluctantly wishes that Vicky was his babysitter again in order to maintain peace. Then, Mr. Turner and Mrs. Turner lost the Reality Contest and entered the Dancing with the Cars contest, only to instantly get hit by a car and subsequently taken to the hospital. At night, Timmy and Jensen are tied by a rope on a train track when a train with Vicky onboard tries to run them over. Jensen asks Timmy that Jensen likes to have a raise and Timmy said that Jensen will get it. In the black screen, before the end title card, The Mayor of Dimmsdale is still running from Chompy. The Mayor said that he loves Chompy.