In Pumps, all is well on Mammoth Island when suddenly Brenda's baking shed has caught fire! Soon, the Mammoth Island Fire Brigade arrives and attempts to put the fire out, using water-filled mammoths. However, young Olive is sure that a machine might make it easier to get water to a fire. Looking at her bicycle pump, she wonders if it might be possible to create a device for pumping water. With the help of the inventor and other islanders, Olive builds a water pump that is soon put to the test and saves the summer barbecue!