Mouse Paint is about 3 white mice who live on a sheet of paper. They discover some paint, and decided to experiment with the paint (like all good white mice are expected to).
This book teaches about primary colours and how secondary colours are formed by mixing the primary colours together.
While this concept may be a little difficult for Samantha, the book is still useful for teaching the names of colours. She also loves the pictures of how the mice dance in the paint in order to mix it around on the paper!