Timmy Turner is excited to gift his cousin Vivian with his fairy godparents on her first day living in Dimmsdale. When her new stepbrother Roy accidentally witnesses the transfer, Viv and Roy are forced to share Cosmo and Wanda.
Roy and Viv turn the people of Earth into mindless dancers after wishing to write the catchiest song of all-time as a way to save their parents' dance studio.
Roy wishes that everything he touches turns to gold despite Viv's objections; when his "Roydas Touch" inevitably goes awry, Roy is determined to save the town from an angry wolf and prove his wish is still golden.
To prove Dimmsdale's nemesis Vicky is only mean because she's lonely, Viv wishes that Vicky would become best friends with the next person she sees, which is Viv; Roy then wishes he were Vicky's best friend to prove Viv wrong.
When Viv learns of Rachel's past failures as a Cookie Scout, she wishes they could enter the Mother-Daughter Competition together; Rachel's extreme tactics get them into trouble, but luckily Roy and Ty end up in the perfect position to bail them out.
Viv struggles to fit in on her first day of school and wishes to become the most popular person at Dimmsdale Jr. High; Roy learns that popularity isn't everything and wishes for a new best friend who will truly love him.
When Ty and Rachel refuse to host Roy and Viv's school dance at their dance studio, Wanda and Cosmo conjure in the time scooter, allowing the kids to alter the past in 1996 as they attempt to change their parents' minds.
Roy unleashes a giant fish monster, Codzillard, on Dimmsdale in an attempt to convince Viv to stay in Dimmsdale after her best friend from Oldsburg tries to persuade her to move back.
Roy does whatever his peers ask to win the class election, but when Viv calls him out Roy accidentally wishes he were a puppet; Viv and Roy wind up on talent show, where Viv will have to help save Roy from losing Wanda and Cosmo forever.
While Wanda and Cosmo are off in Fairy World, Roy and Viv use Da Wish App to grant their wishes, until they inadvertently unleash a horde of zombies in their home on Hornet Day.
Vicky sets out on her evil plan to free Mr. Crocker and capture Cosmo and Wanda; at odds over whether it's best to make wishes for yourself or others, Viv wishes for her own talk show to help people, and Roy wishes for a "Roy Day" party.
Viv and Roy must resolve their differences and come together to rescue Cosmo and Wanda, and stop Mr. Crocker and Vicky's evil plan to control and take over the Fairy World.
