Pip first appears at Giselle's hollow tree house and (but not quite) saves her from a troll. When Narissa pushes Giselle into a well, Pip witnesses this and rushes to alert Prince Edward. They travel to New York City the next day, but as soon as Pip arrives, he realizes that he is barely able to speak. He figures out Narissa and Nathaniel's evil plot to kill Giselle and tries to warn Prince Edward, but he misinterprets all of his movements. He is then captured by Nathaniel but manages to escape and find Giselle to tell her about Prince Edward.
He becomes captured again when Nathaniel finds him and traps him in a plastic ball. However, he manages to escape and roll his way up to the Woolworth Building. Prince Edward releases him, and he immediately rushes up to help Giselle and Robert defeat Narissa.
After everything was over, he returns to Andalasia and publishes a book about his experience in New York, which turns him into a celebrity.
Pip is probably based on Timothy Q. Mouse in Dumbo. Like Timothy he assists the hero, and (in his animated form) speaks with a New York accent.