Dan and Cat have had to make the biggest decision of their lives. It is no surprise that it leads to an experience which will stay with them, and one they will need to draw upon many times in their future.
It is called apsorbirati; the process of feeding on another human being's energy.
Just as they are getting their heads around this new-found skill and are slowly settling into new life, the school is compromised and a pupil is abducted.