In the real world, Original Sin refers to the sin Adam and Eve committed by eating the fruit from the tree of knowledge. They saw the reality of the world around them and suffered as a result.
Here, Spenser is hired by a priest to look into the suicide death of a young woman about to become a nun. Her family doesn't want Spenser stirring things up, but he persists. He finds that a crook is donating money to the church, and that the girl was striving to help people who were being evicted from their homes. Then he finds out the girl was pregnant.
Spenser first suspects the priest of having corrupted the girl, but after a boxing match he decides the priest is a good guy. He then suspects one of the girl's co-workers, and that guy is promptly killed. In a sign of how Hawk is becoming fond of Spenser, Hawk just "shows up" to shoot a guy that is about to kill Spenser.
It turns out the crook is working with someone at the church. They are evicting the poor so they can build something new on the land. So that all gets wrapped up, but it still doesn't explain how the girl died.
Finally we learn that the mom had gone to talk with the girl, and was yelling at her. The girl backed up and fell accidentally to her death. So it was an accident after all.
This is the first time Hawk really backs Spenser up fully as a matter of course. There are interesting scenes of the Boston Marathon worked into this.
Spenser for Hire TV Series episode listing
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