The kids are spending a fun day with Gramps, but Boy and Girl are so absorbed in a new game they are playing that they don't get into the swing of the activities he has planned. They try to put it right when they realise that this has hurt Gramps's feelings, but end up putting all the kids in danger! 

When Dog invents a gadget that allows him to play fetch alone, Cheese is convinced it will be a runaway success. However, Mouse is desperate to hold on to his place as family inventor.