Wizard's First Rule
Along the way to the pass, Richard and his friends are attacked by underworld creatures.  This encounter leaves both Zedd and Chase in a state of sleep.  Soon after this event takes place, Richard and Kahlan reach the home of Adie.  Adie is a bone sorcereress, and is the only one who can tell Richard and Kahlan how to get through the boundary.  They leave Zedd and Chase in Adie's care, and cross through the boundary.