The Void Emissary are the peacekeeping force of the Twelve Worlds. Some of them belong to the Order of Hunters, those charged with assassinations. Pieter Strahd is one of them and he is given a mission to kill someone or the Twelve Worlds will sink into chaos.
Soon he is joined by Kyp, a young aethernaut, and Sarena Corr, with a living tree ship as transport. All of them together struggle against a mysterious force that could swallow all of the Twelve Worlds.