The Tree is all the world to those who shelter in its branches; but it seems that the Tree may be dying ...
Samiha was put on trial on charges of grand heresy and thrown off the docks in Argos city, into the mists of the World Below. Still grieving for the loss of his love, Tymon is exiled by the priests and condemned to a life of slavery in a southern Tree-mine. Flogged for his insubordination, he is helped in his recovery by a worker named Zero.
When disaster strikes the mines, Tymon and Zero escape into the tunnels and wander for many days through the heart of the Tree. Tymon hopes he will locate the Oracle and understand the visions of Samiha that have plagued him since her death. But war and rebellion are tearing the world of the Tree apart, and there are others searching for the Oracle. None of them are prepared for what they find.