Hannah Taylor and her border collie, Tammy, have a special bond. They have grown up together and are so close they practically know each other's thoughts. But when Tammy suddenly falls ill and dies, Hannah is devastated and wonders how she will ever cope with life without her beloved friend.

But life goes on and Hannah must face a new year at high school. Despite the help of her family and friends Hannah misses Tammy so much she loses interest in everything, even the famous summer fayre which occurs every year in the village.

Meanwhile Tammy is also struggling to work out what is happening. After being desperately ill and falling into a deep sleep, she is now feeling better than ever. But Hannah no longer seems able to see or hear her. What's happened? What's this limbo Tammy has suddenly found herself in? And what's this strange light that follows her?

When a cute, fluffy collie pup called Willow comes into their lives, Hannah cannot help but grow fond of this little ball of fluff. And even better, this little pup is no ordinary dog, she can actually see Tammy.