New teacher Miss Mistry is taking Class 3C on an outing to the Flumes ‘o’ Doom water theme park, and if anyone is a micro-second late, the bus leaves without them. 

Dennis has been struggling with time-keeping, and Walter pulls out all the sneaky stops to make Dennis late for the bus. Will Dennis get to splash down with the rest of his pals or will Walter make sure it's all downhill for our blam-tastic hero? Tune in to find out!