School starts tomorrow and Anne, Nick and Shania are doing test runs of a rocket messenger system so that they can stay in touch during the school day. Unfortunately, one of their rocket attempts accidentally collides with a pigeon. As Shania and her Grandma nurse the pigeon, Anne and Nick realize that they need something smarter and more adaptable than a rocket to be able to carry messages. That’s when an ordinary pigeon becomes Harrier Pigeon.