One day, Daddy Rat announces to his baby rats that he'll be taking them to the zoo . . . but only if they're good, which means no talking about poo! And yet, before the family can even leave the house, the two rascally siblings can't help but wonder . . . what sort of poo would an astronaut do? Shiny, silver, space-age poo! Rocket-powered, weightless poo, and it spins round and round like a planet does, too!

Head chefs, balloon sellers, blue whales . . . everyone and everything must have a unique poo, and the siblings simply have to stop and imagine each and every one (much to the chagrin of Daddy Rat, who is getting increasingly irritated with all the poo talk). Once the rats finally reach the zoo, things escalate, because of course each and every animal in the zoo must do a special kind of poo! Finally, Daddy Rat has simply had enough, and is forced to sit down and explain the facts to his curious kids. And when he thinks he may have gotten through to his youngsters, he encounters a surprising (and smelly) twist which will have little rats everywhere laughing out loud!