slowly losing herself to Alzheimer's. And Henry is still dealing with the grief of his boyfriend's suicide last year. Wiping the slate clean sounds like a pretty good choice to him. But Henry is a scientist first, and facing the question thoroughly and logically, he begins to look for pros and cons: in the bully who is his perpetual one-night stand, in the best friend who betrayed him, in the brilliant and mysterious boy who walked into the wrong class. Weighing the pain and the joy that surrounds him, Henry is left with the ultimate choice: push the button and save the planet and everyone on it...or let the world--and his pain--be destroyed forever.