Frankie and her sister are unicorn crazy! Today, they're playing their favorite unicorn game, but when their bossy friend Ada arrives with her brother to play, she takes over the game--and takes over Frankie's wheelchair--putting them all in unicorn prison. There is only one thing to do--it's time to be bad unicorns!

The author deftly handles the subject of childhood play and disability from her own personal experience of growing up with a sister with a disability.