Reading has no place in the summer plans of tomboy Kate . . . According to Kate, "Every kid needs a place of her own, a spot where a visitor comes by invitation only. It doesn't have to be hidden from sight, but it does have to be hard to reach. I mean, it should take a lot of effort to get there, like in the middle of a swamp or on the top of a mountain. My tree is like that. You have to climb 16 steps straight up the ladder to reach my fort. No grown-up has ever tried. That's what makes it exclusive to everybody except my friend, Hug, who is always invited." Kate has it all-a place of her own, shared with her best friend, Hug, where they look forward to a carefree summer together, a time when she will learn to whistle, a time when they will solve the mystery of the Bush Monster. But, suddenly, Kate loses it all and finds herself alone and grounded, and faced with a "condition" she must overcome. Even worse, Hug had told her they would be friends forever; now he is gone, leaving her to wonder how forever works. This summer, with the help of a most unlikely new friend, Kate learns some of life's most important lessons as she experiences the power of love on many levels. Whether you are seven or seventy, you will cheer (or whistle) as Kate invites you, the reader, to her triumphant tree house finale.