From the back cover:
"Have you ever heard the phrase "quick like a bunny"? People say it all the time about me. It means that I am fast. But I just met something that's even faster than me. And guess what? It's a cute and fluffy bunny! I am bunnysitting for my friend Lily. Bunnysitting means I am caring for her bunny - not sitting on it. Obviously. Watching a bunny is easy, unless you have an imaginary friend named Posey who draws doors to the World of Make-Believe and leaves them open. Because Lily's pet is quick like a bunny, and it loves to run through open doors."