Muna's fortunes changed for the better on the day that Mr. and Mrs. Songoli's younger son failed to come home from school.

Before then her bedroom was a dark windowless cellar, her activities confined to cooking and cleaning. She'd grown used to being maltreated by the Songoli family; to being a slave.

She's never been outside, doesn't know how to read or write, and cannot speak English.

At least that's what the Songolis believe.

But Muna is far cleverer—and her plans more terrifying—than the Songolis, or anyone else, can ever imagine.