A boy, just 15, through no effort of his own, travels back in time to the late 15th century, where he meets Leonardo da Vinci. Because the universe bends back on itself, time streams overlap, and he just happens to be in the right place at the right time. Or the wrong one. Da Vinci, in addition to being an artist, was an early futurist, who drew designs for the first airplane, helicopter, submarine, and on and on. Who better to design a time machine to get the boy home? Not a great student, our time-traveler is hooked on natural science as he gets to know Leonardo. Meanwhile, da Vinci is...