Parallel Magic

A complete urban fantasy trilogy, intended to be read alongside the Order of the Elements series.

Bria has spent the last five years lying low after escaping the deadly magical prison of the House of Fire, but when her best friend is kidnapped, she has little choice but to trust a rogue spirit mage and hide among the contenders for the coveted position of the Fire Element in the Court of the Dead. 

Parallel Magic takes place alongside the Order of the Elements series and many of the characters overlap. To avoid spoilers, I'd recommend reading the first three books in that series first.