Cate Blanchett plays Penelope has short, dirty blonde hair in a bob cut styled into curly ringlets and a pink headband with a bow that she wears just past her bangs. She is a little girl who wears a short-sleeve white button-up blouse with a peter pan collar with a navy blue suspender skirt, complete with white socks and matching navy blue Mary Janes.
Stewie Griffin meets Penelope (Cate Blanchett) in the park after he is bullied by another boy. She gets revenge on the bully by giving him superglue laced taffy, presumably choking him to death. When Stewie plays at Penelope’s house, he discovers that she has the same fascination with weapons as he does. However, she was actually successful in killing her mother by decapitating her. Stewie instantly becomes infatuated with her, and together they cause chaos in several parts of the world. Meanwhile, Brian Griffin notices that Penelope is becoming a bad influence on Stewie and stages an intervention.
In the past, Stewie’s ambitions were to rule the world, whereas Penelope wants to cause war, chaos, and destruction to the world for nothing more than personal amusement. When Stewie tells Penelope that Brian told him not to see her anymore, she asks him to kill Brian. Stewie was not able to kill him, so Penelope decided to do it herself.
Stewie intervenes and they both start fighting. They have a laser gun fight, and Penelope traps Stewie with an anti-gravity gun, but Stewie uses a gadget to reverse the polarity of the anti-gravity gun to escape. They both fight over the anti-gravity gun and fight in its beam until they wind up on top of a moving truck. When Stewie gets the upper hand in the fight, Penelope agrees to leave Brian alone. Then, she kisses Stewie goodbye and rides off with a smile.
