A boy unearths a pocket-sized time travel device that could change his life . . . or end it . . . in this classic science fiction adventure. "Sleator's expert blend of future and horror fiction is unusually stark, dark, and intriguing. And the breakneck pace never falters." — School Library Journal When eleven-year-old Tycho discovers that the mysterious egg-shaped object he dug up in his garden is a time travel device, he can't resist using his newfound power. Soon he is jumping back and forth in time, mostly to play tricks on his bossy older brothers and sister. But every time he uses the device, he notices that things are different when he gets back—and the futures he visits are getting darker and scarier. Then Tycho comes face-to-face with the most terrible thing of all: his grown-up self. Can Tycho prevent the terrible future he sees from coming true? "The combination of logic and horror gives the telling a Poe-like quality." — The Horn Book