This is the third book in the War of the Spider Queen series. After emerging from the portal that they used to escape Ched Nasad, the drow party plans its next phase of the mission. They decide to consult a priest of Vhaerun to see if any of the other deities know what has become of Lloth. Luckily, Valas Hune knows where such a priest can be found and believes that this priest may help them in their quest.
Valas' friend is far away, however, and the last thing that the party wants is to travel a huge distance to get to them, so on Pharaun Mizzrym's advice they decide to shadow walk to get there. The journey has some minor battles but nothing this group can't handle. They end up back in the Underdark after their journey and in the Domain of the duergar. It becomes evident that to get where they are going, they must travel through the home city of the duergar and will need passports to get through unharmed. The group rests for days in the city while they search for means to obtain these documents.
Meanwhile in Menzoberranzan, Gromph Baenre learns of an impending duergar invasion, and rushes to alert the ruling council until the lichdrow Lord Dyrr stops him. A duel is fought in Gromph's own sanctuary, but the lich prevails and imprisons Gromph in a glass sphere.
Eventually, Matron Triel Baenre does learn of the impending duergar attack (Nimor Imphraezl posing as a drow commander from House Agrach Dyrr informs them), and the decision is made to send Menzoberranzan's army to the Pillars of Woe to destroy the duergar. Nimor's trap is thus set.
The Army of the Black Spider is almost utterly destroyed in the ensuing encounter (and would have been if it were not for the ferocity of House Baenre troops). The army limps back to Menzoberranzan, leaving a token force behind to slow the duergar.
Quenthel Baenre's drow party eventually escapes the duergar city and makes it to Valas' contact (Halisstra Melarn is captured by surface elves during this journey). They are told by Valas' priest friend to journey to Myth Drannor and acquire a magical item. After an intense battle with devils and a beholder, the group finally returns.
The last part of the book entails the party's journey to the Abyss (in astral form, not physical) to inspect for themselves what has happened to Lloth. They come to a great barrier to Lloth's domain in the shape of a huge visage of a female face. They are powerless to get through the barrier and are about to give up when the god Vhaerun materilizes and strikes the visage with his godly power. He is about to break through when the god Selvetarm (Lloth's guardian) materializes and fights him. The drow party realizes that the power of the gods is too much for them and must kill the priest of Vhaeraun to escape the Abyss. They flee the stronghold of the priest stunned and shaken.
The longest book of the series by far, Condemnation is full of action and suspense. Also in this book is the first time Quenthel is seduced by Danifae... an event that has long lasting repercussions through the series.