Annie Shearer lives in the country town of Upson Downs with her best friend, an adopted stray dog called Runt. The two share a very special bond.

After years evading capture, Runt is remarkably fast and agile, perfect for herding runaway sheep. But when a greedy local landowner puts her family's home at risk, Annie directs Runt's extraordinary talents toward a different pursuit--winning the Agility Course Grand Championship at the lucrative Krumpets Dog Show in London.

However, there is a curious catch: Runt will only obey Annie's commands if nobody else is watching.

With all eyes on them, Annie and Runt must beat the odds--and the fastest dogs in the world--to save her farm.