The book is an expansion of Leiber's earlier novella "Scylla's Daughter", which was published originally in the magazine Fantastic Stories of Imagination for May 1961.

The Fafhrd and Gray Mouser stories concern the lives of two larcenous but likable rogues as they adventure across the fantasy world of Nehwon.

A sea serpent ridden by an explorer from another world is encountered, but the true foes prove to be legions of intelligent rats.

Returning to Lankhmar, the protagonists find the whole city besieged by the rats.

"Scylla's Daughter" was nominated for the 1962 Hugo Award for Short Fiction.