Ten year old undercover super sleuths, Rosie and Tommy and their sidekicks a super clever sheep, nicknamed Brains, and a death defying duck, called Puddle, set off to collect a top secret parcel. The parcel has to be delivered to Sadie a mysterious old lady who recently moved into a tiny caravan in the middle of the village field. Before they get very far they find themselves zooming across space and time to an alien planet where they meet strange creatures, survive high speed chases and gradually unravel the parcel's secrets. But will they be able to get the parcel back to planet Earth and deliver it safely to Sadie? And will they finally solve, 'The Suspicious Case of Sadie and her Unusual Pets'?