At the Houston Zoo a twenty two-month wait is almost over. Shanti the Asian elephant is due to give birth. But no-one knows exactly when the great event will happen and tension builds as the days pass, especially as the zoo keepers know Shanti has a volatile temperament and the birth will be fraught with danger. Meanwhile, the zoo vets must also decide what to do about a suspected cancerous growth on the leg of a chameleon, and the carnivore keepers set a challenge for their Malayan tiger.