PJ is really looking forward to his birthday. His grandfather has promised to take him to opening day at the ballgame. So when his swim coach organizes a mandatory practice on the same day, PJ decides he'd rather quit the team.

At the same time, his new video game keeps turning on randomly and scrolling "One if by land, two if by sea," across the screen-and it's a game about robots, not the American Revolution.

Things get really weird when a freak storm transports PJ and his sister Sammy back in time to 1775 Boston. There they meet Copper, a colonial kid helping Paul Revere gather...