Joey dresses up as a superhero for a costume contest by putting on a mask and cape. He thinks his costume is the best and that he is sure to win. However, his mom asks him to watch his little sister Mindy at the party. Joey complains that superheroes don't have kid sisters but his mom insists this superhero does. Joey finds a baby blanket and uses it to turn Mindy into Supergirl so they can go to the party together, where they win first prize as a superhero team.