Walking through the misty Florida woods one morning, twelve-year-old Rob Horton is stunned to encounter a tiger - a real-life, very large tiger - pacing back and forth in a cage. What's more, on the same extraordinary day, he meets Sistine Bailey, a girl who shows her feelings as readily as Rob hides his. As they learn to trust each other, and ultimately, to be friends, Rob and Sistine prove that some things - like memories, and heartaches, and tigers - can't be locked up forever.