Saving Grace: a Person of Interest fanfic
There is a machine that watches over the entire country, understand, and can foresee crimes. The Machine picks out the social security numbers of those involved in a crime, and sorts them into two categories: Relevant and Irrelevant to national security. Every night at midnight the data is erased. The government acts on the relevant numbers, and Harold Finch-the Machine's creator- and John Reese act on the irrelevant numbers. Because of what he was doing, Harold's fiance, Grace Hendricks was put in danger, so he staged his death to keep her safe. But, what would he do if her number came up in the Machine?