Home again, but with one more mystery to unravel. Who - or What - lies 'Below' the Library? And when will they return? With trade goods going missing, and a need to build closer ties between the Library and the mantids, Marsh and Roeglin look to have their work cut out. They must also find ways to train Tamlin and Aisha as one discovers how to step between spaces, no shadows required, and the other learns that lightning exists in more than just the dark... ...and then there is winter... ...and the threat haunting Marsh's nightmares and eyeing the Devastation for conquest.