The plot is set in the Zoological Gardens adjacent to the bear pit and tells an amusing story of the lovelorn plight of Aesculapius Carboy, madly in love with Laetitia, whose father has forbidden them to meet. Needless to say the complications of the plot are sorted out and everything ends happily.

'The Zoo' was first produced in the same year as 'Trial By Jury' upon which it is clearly modelled. The libretto was written by B. C. Stephenson under the pseudonym of 'Bolton Rowe'. Sullivan completed the score only two days before the opening night and after several short runs up until 1879 it was lost to public view. The music was never published, the manuscript was left in a London bank and only revived in the last few years to delight new audiences.