Wish on a Unicorn — Karen Hesse

Now I didn't believe a broken-down old unicorn could make wishes come true . . . not for a minute. But what if it could?

Mags has a lot to wish for -- a nice house with a mama who isn't tired out from work; a normal little sister; a brother who doesn't mooch for food; and, once in a while, she'd like some new clothes for school. When her sister Hannie finds a stuffed unicorn, Mags's wishes start to come true. She knows the unicorn can't really be magic, but she won't let anything ruin her newfound luck -- even if it means telling her own sister to believe something that can't possibly be true.