Marissa loves her big brother, Mario. He always comes up with fun ideas. When playing in their nana?s backyard, they decide to make some wormy, squirmy mud tacos. That gives Mario an idea?how about some real tacos for lunch. Before long it is off to the store with Nana, but first they must pick up their cousins Rosie and Chico. When Chico starts acting like a hotshot to prove that he is a big kid, can his cousins, with the help of a few mud tacos, show him how to have some real fun?