, a gluttonous grey fox known for stealing food, finds and eats a mysterious green egg. Shortly after, Rozo becomes paralysed while attempting to hunt a large bird (the ). To solve the case, three clever animal detectives— (a toad), and (a mule)—must investigate the poisoning.
, a silver-tailed gray fox known for stealing eggs, finds a bright green egg at his burrow entrance. After eating it, he falls gravely ill from poisoning. The local police, led by the grumpy dog el libro el enigma del huevo verde pdf