As Maggie approaches her thirteenth birthday, she wants to believe that some kind of magic can stop the changes all around her. Her visit with her father and his new family at a lakeside cabin makes her wonder. Will he still love her as much, now that he has a new family, or will he love her baby half-sister more? Her father seems troubled and withdrawn and, while he insists nothing is wrong, she worries.

Alone with her own secret thoughts, Maggie finds comfort in the beautiful blue heron she visits at the lake every morning. With each visit, she grows more attached to the bird, and she becomes aware that someone else is watching, too -- someone who's putting the bird in great danger. Through her determination to protect the bird, Maggie begins to understand the magic of change in her own life, and in the constantly changing world around her.