The First One is a serial killer's first murder, the events leading up to it, and what he felt afterwards.
The First One is a short story that raises the question of what happens when belief in the afterlife is gone. When an individual believes there is no penalty for doing 'bad', or reward for doing 'good'. What happens when each individual thinks there are no spiritual consequences, and that 'good' and 'bad' are for each individual to define.