The Sentinel

Pete Garrison, a seasoned Secret Service agent, engages in a secret affair with First Lady Sarah Ballentine. The affair complicates Garrison's professional life as he balances his duty to protect the First Lady while keeping their relationship hidden.

Garrison's close friend and fellow agent, Charlie Merriweather, is brutally assassinated outside his home. This event raises suspicions of a larger conspiracy and alerts Garrison to a potential threat against the President.

Garrison receives crucial intel from a trusted informant who links Merriweather's murder to an assassination plot targeting the President. The informant's information reveals that there is a mole within the Secret Service.

The Secret Service's Protective Intelligence Division, led by Garrison's former protégé David Breckinridge, begins investigating the assassination plot. They start their inquiry by polygraph testing all agents to uncover the mole.

The mole within the Secret Service uncovers Garrison's affair and attempts to blackmail him. Garrison is lured to a coffee shop, a known meeting point for Colombian gangs, further complicating his situation.

During the polygraph testing, Garrison fails due to lies about his affair with the First Lady. Consequently, he becomes the prime suspect, falsely accused of leaking information to the assassins.

Breckinridge confronts Garrison at his home, leading to an intense interrogation. Their estrangement becomes apparent as past grievances, including Garrison's rumored affair with Breckinridge's wife, resurface.

Desperate to prove his innocence, Garrison embarks on an independent investigation into the assassination plot. He contacts the informant, only to discover he has been murdered, raising his stakes even higher.

Garrison, through his network of contacts, discovers an apartment linked to the assassins. He learns they are headed to Toronto for an attack on the President at the G8 summit, escalating the urgency of the situation.

In a critical moment, the First Lady confesses her affair with Garrison to Breckinridge. This revelation leads Breckinridge to doubt Garrison’s guilt and sets the stage for their reluctant partnership.

Breckinridge and Garrison work together to uncover the mole, revealing senior agent William Montrose as the traitor. They realize Montrose is responsible for the security breach and must act quickly to save the President.

At the G8 summit in Toronto, Garrison and Breckinridge race against time to prevent the assassination of the President. The assassins disguised as law enforcement officers initiate their deadly plan.

Montrose, under threat to his family, ultimately decides to take action against the President, despite knowing the implications. His last act leads to a tragic end as he is killed while trying to protect the President.

In a tense climax, Garrison confronts the Handler, the leader of the assassins. He manages to save the First Lady from imminent danger, showcasing his commitment to protect her, despite the fallout of their affair.

Following the dramatic events at the G8 summit, Garrison is forced into early retirement due to the public scandal regarding his affair with the First Lady. As he leaves the White House, both he and the First Lady share a bittersweet farewell.