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.

Vicky sets out on her evil plan to free Mr. Crocker and capture Cosmo and Wanda. Meanwhile, 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.