The book's plot describes the way in which an outcast animal, the scub, infiltrates the ark and introduces certain of the other species to the idea of eating meat.
For example, the nautically naive Noah initially constructs the ark with all the large animals quartered together for social reasons, only discovering the consequences for its stability when the flood waters surround it.
Like many later fictionalisations of the Noah story, from Gary Larson to Julian Barnes, it introduces mythical beasts such as the unicorn into the Ark's passenger list, a device with obvious dramatic potential: we assume that such creatures are unlikely to survive the voyage.
Especially memorable is the plight of the 'Seventy-sevenses', a pair of nondescript and painfully shy mammals who name themselves after the number of their cabin, and who eventually abandon the Ark on a small raft because the atmosphere on board has become too oppressive.
In the final scene, a horrified Noah – who has not yet realised quite what has happened on his ship – watches as the newly released animals chase and fly from one another, awakened to their new identities as hunters and hunted.