Foreword
"Or What Came Before"
The first three books of The Crystal Halls detailed the battles between the clans over supremacy of the Undercity with the end of The Sapphire Stratagem dealing with how the city elf, Dominion Thule, won creating a single clan to oversea the crystal trade. At the beginning of Chains of Obsidian, Pandora leads Kuma into the Eternal City, the dangerous home of the city fae, on a quest to find her former mentor in hopes of acquiring the skills she needs to take on her grandfather.
In the Eternal City, they survive an encounter with the Ruby Court queen and eventually make their way to Hylakane, the Steel Sun, who reluctantly takes them as his students. The two waku learn to push themselves past the limits of what they thought possible. Pandora, in particular, passed the Trial of Wraithhawks, learning a valuable lesson and acquiring an artifact in the shape of a wraithhawk mask. Afterwards, they return to the Undercity, prepared to take on Dominion Thule.
While they were away, the other surviving members of Razor and Drops clan—Choo-Choo, Yara, and Tick—wage guerilla warfare against the Alliance. They're eventually aided by the other former members like Vasilisa, or Camina, but their attentions to the cause fail to make more than a small dent in the Alliance's takeover of the Undercity. At the end of the book, after Vasy's Alliance boyfriend Andy is killed, they make a plan to stop Dominion Thule.