Rusty lives with his dragon Cole and faithful friend Bo in the kingdom of Scrapland, a magical world completely made of scrap-metal. With dreams of winning the great knights' tournament, Rusty acquires a speedy engine for his horse Chopper that propels them into first place. But when the engine turns out to be stolen from ambitious Prince Novel, brave Rusty must redeem his knightly honor, save the kingdom and prove that true friends always stick together.

Too bad: Knight Rusty's big show fight in honor of the Knights of Scrapland completely backfires and plunges the kingdom into total chaos. The king rages and sends the knights all to the devil. While Miss Bö goes to work and the dragon Koks takes care of the household, Knight Rusty sits alone in the cellar and mopes. Until there he meets Gespenst, his father's former assistant, one of the greatest inventors of Schrottland. And Knight Rusty decides to complete his father's work. Will our tin hero manage to restore the honor of his friends with the help of his inventions?