Is the zoo getting rich from selling the animals' poo? After overhearing that zoo poo is valuable, self-obsessed gorilla Jurgen is convinced the zoo's poo is being sold behind his back. To stop anyone cashing in, he calls a poo strike - no-one is allowed to poo in the zoo. But as time passes, it becomes more and more difficult for the animals not to give in to the urge, and when a mystery poo is discovered, the 'No Poo Zoo' is gripped by a puzzling case of 'poodunnit'.