Mona is first seen walking with Max from the ticket booth at the train station and seeing him talking to his father, Goofy on the phone.
The train takes Max and Mona to his hometown and they fall asleep next to each other on the train ride. Afterwards, she is seen on the train and then walks off to Goofy’s car. And after that happens, Goofy seems to accidentally keep embarrassing Max by showing Mona Max's baby pictures. Mona is seen making popcorn with Goofy while Max takes a walk outside, When Max comes back to the house, Goofy and Mona make popcorn but Goofy puts too much in the popcorn machine. The popcorn turns the rooftop of Goofy and Max’s house into a "more snowy" house, Mona laughs about what had happened, exposing her buckteeth that are identical to those of Goofy and Max, and they make snow angels on the roof.
Mona was inspired by Roxanne because originally Roxanne was supposed to be in film. But due to limitations of CGI Animation in 2004 it would have been a nightmare to animated Roxanne's long hair.