During another mundane, grey day in London Jungle, siblings Dennis and Dade discover that the world was once a bright and cheerful place, and that the heroes of their favorite book, The Terrific Teacups, were more than merely works of fiction, they were the pachyderm pair that kept the city safe from the selfish and oppressive creatures who now rule it. The daring siblings must find a way to bring their heroes back and restore beauty and color to a world that has forgotten it.