A New York police officer uncovers the real identity of his houseguest an IRA terrorist in hiding.
This is a what if scenario, like if the film was made between 1990 and 1992, and based on Kevin Jarre's original script which can be read at the following link.
https://archive.org/details/the-devil-s-own-kevin-jarre-third-draft-revised-december-14-1990