Star and Marco are put in charge of watching Buff Frog's tadpoles. Marco wants to follow the Buff Baby handbook, while Star just wants to cuddle them and poke at them. Things get complicated when the tadpoles sprout their legs and hop around.
After having skirmished with a number of dangerous monsters, Star Butterfly arrives on Earth to live with the Diaz family. However, rather than living a normal life, Star continues on having to battle villains both throughout the universe and in their high school, although if only to protect her extremely powerful wand, an object which she is still confused with.