"We made a promise, remember? To save everyone. Back then, we were too young. When we were older, we were too weak. Now? Now there's nothing in my way and nothing left to lose." A young doctor exploring the world, a prodigy searching for her place in the world, and an orphan hunting for clues about her father's murder. Their journeys converge on a job granted by a mysterious benefactor that will entwine them in a world of subterfuge where the future of the world hangs in the balance.