After the IRA shoot down a minister in front of his London home, the government send an SAS man undercover to Dublin to track down the killer against the advice of the army and intelligence.
While Harry begins a relationship with a local girl, the Special Branch launch their own investigation which leads to the suicide of a young woman. The IRA learn about Harry from a careless remark made by Col. Frost in a restaurant.
Harry finds out the identity of the man who killed the minister, but with the IRA on his tail, going after all of his known associates, he finds it hard to complete his mission.