Modesty's latest adventure takes place in the jungles of South America, where she and her loyal henchman, Willie Garvin, take on the evil Mistress of Limbo. The Mistress has enslaved the people of Limbo, including Modesty's friend Danny. After a failed kidnapping, Modesty learns of her friend's enslavement and sets out to rescue him and set Limbo free. In an adventure that spans London, Switzerland, and New York City, Modesty ends up in Guatemala, where the Mistress of Limbo has commanded that Modesty be sacrificed to the gods. With Willie at her side, Modesty must fight a Mayan priestess to free herself and the slaves on what will be the last day in Limbo.

Tia Benita, the crazy aunt of a man named Paxero, initiates a daring plan to kidnap Modesty Blaise, but the plan is upset by an unexpected argument between Willie Garvin and Paxero.