So, I finished Benedict Jacka's Hidden on the way into work today.
Much like Simon R. Green's work these days, there isn't much material here to really review without getting spoiler heavy, sadly. Which is bad, since this book delves deeper into themes about the differences between Dark Mages and Light Mages, and the grey area Alex operates in.
But basically, Ann, the life mage gets kidnapped early on after dropping out of the Light Apprentice program. This sucks in the usual cast to figure out where she is and why she was kidnapped.
When they finally get that far, it ends up being Alex on his own entering a Shadow Realm owned by Ann's former master, Sagash. Which also allows for the first current time appearance of Alex's former Dark master, Richard. Whom, it seems, has returned from where ever it was he vanished off to before the series started. Richard, who offers a deal that both Ann and Alex refuse.
However, we also learn of Ann's training under sagash and why it is she's such a pacifist.
It's a fun read and addition to the series, although much of it seems to exist mainly to beef up plot lines down the road.