Kat and Ari love cookie time, their special tradition with Grandpa and his dog, Biscuit. It's always fun and oh, so delicious! But waiting for the cookies to be ready is so hard. What better way to skip to the good part than a time machine?

The two plan to jump a little into the future, to when the cookies are out of the oven, but they overshoot and go way too far ahead! And when Kat and Ari try to return, they still can't get the timing right. They have fun meeting prehistoric dinosaurs, futuristic robots, and even past versions of themselves...but just wish they could get back to Grandpa. Could they have been wrong about the best part of cookie time?