Alex is trying to rebuild his life with his Kin girlfriend, Silhouette, and deal with his newfound abilities. This doesn't last long, as he's soon enlisted into a clandestine operation to head off some impending doom foretold by Seers linked to Alex's destiny.
Elsewhere, when a company called the Black Diamond lets Claude Darvill know his father has gone missing after chasing Alex Caine, Darvill decides to take up the hunt himself.
And some amateur mages in Britain's north think they have uncovered ancient magic that will reveal unto them great powers. However, they are caught in a vortex and pulled through to a strange lost city, isolated in the void, taking Alex and company along for the ride.
Trapped in a place removed from everything they know, ruled by a hierarchy of monsters, Alex and his friends must find a way to escape Obsidian.