Life has been difficult for Ben Coffin and he doesn't make friends easily, so he spends most of his time with his favorite characters from science fiction books. One day he rescues a scruffy dog on the way home from the library. The dog, who he names Flip, then leads Ben to befriend Halley, a girl who dresses in crazy colors. Ben nicknames her "Rainbow Girl," and together Ben and Halley decide to write a novel. In doing so, Ben's life unravels. If he wants to keep his new friend, he will have to figure out what friendship really means.