Lark Greenpool became a Guardian at just the wrong time. A forbidden artifact known as a Bloodring has been awoken. It released a malevolent energy that threatens to destroy the barrier that protects Lark's world from the Outside and it's the Guardians' job to put it right.
Help arrives in the form of an ambassador from the Ringsworn, the people who made the Bloodring. Violet Ironwrought is prickly, most likely very dangerous, dislikes everyone, and is completely fascinating to Lark. After a rocky start, friendship blossoms between the two women, and slowly grows into something much more than that.
When circumstances threaten to separate them, Lark has to decide where her loyalties lie, and what she is willing to risk to protect not only herself, but the woman who has become the most important part of her life.