Bickering frenemies Meg and Shar are doing some serious damage at a midnight sample sale when the fashionistas find themselves arguing over a pair of shoes - with fatal consequences. One innocent bystander later, the girls are suddenly at the mercy of Hades, Lord of the Underworld himself. To make them atone for what they've done, Hades forces the teens to become special-assignment Sirens, luring to the Underworld an individual whose unholy contract is up.

Finding that delicate balance between their fashion addiction and their new part-time job in the eternal hellfire biz turns out to be harder than Meg and Shar expected, especially when an entire pantheon of Greek deities decides to get involved. Then there's the matter of the fine print in their own contracts?