The story of Gilberts Dragon introduces the Science Rangers, the teacher Ms. Daly, and the students in Room 3 at Lake Pleasant Primary School. Room 3 has an unannounced visitor join them for the day. The intruder has four legs, a tail and a cheeky smile with a lot of teeth and is usually found in deserts and arid environments. His scientific name is Lophognathus Gilberti, more commonly referred to as Gilberts Dragon. His owner calls him Bertie. The class were engaged in 'Shared Reading" when Bertie made his dramatic and frantic entrance. Having had very little to eat for breakfast he goes in search of the food in the children's lunch boxes and back-packs.

Ms Daly tries her best to put a stop to the chaos in the classroom. However, it was the Science Rangers who saved the day.