Digit's friend Pearl says her town is in trouble. The water levels in Canalia, a beautiful cybersite connected by canals, keep getting lower, but Canalians don't see the problem. So Pearl built a time machine to prove she's right! She travels with the CyberSquad into the past to see how much higher the water levels were, and the kids promise to help convince Canalians to change their water-wasting ways.But when they invite everyone to travel through time and see what happens, the time machine goes missing! Hacker has stolen it! Can the kids get the time machine back before Hacker resets the course of cyberhistory?! And can Canalians be convinced to protect their future by changing the present?