The Sentinel

Alison Parker moves into the top-floor apartment of a historic Brooklyn Heights brownstone, drawn by its character but unsettled by the building's past. She notices the presence of a blind priest, Father Halliran, who sits at his window as if watching over the place. The move marks the beginning of a troubling sequence of uncanny events.

Alison begins experiencing fainting spells, insomnia, and eerie noises echoing through the halls. She meets the eccentric Charles Chazen and the lesbian couple Gerde Engstrom and Sandra, whose odd behavior disturbs her, including an unsettling cat birthday party. The atmosphere grows increasingly ominous as the strange occurrences pile up.

When Alison complains to Miss Logan, the rental agent, she is told the building is occupied only by Halliran and Alison. The claim fuels suspicion that something supernatural or forbidden hides behind the walls. The contradiction intensifies Alison's sense of being watched.

Alison's lawyer boyfriend Michael Lerman enlists his corrupt detective friend James Brenner to probe the strange happenings. Brenner's involvement promises a practical explanation, but hints at darker forces at work. The inquiry signals trouble ahead for everyone involved.

Brenner visits the building and Alison comes face to face with the animated corpse of her deceased father. She fights back by stabbing the apparition and is hospitalized with a nervous breakdown. The night marks a chilling breach between the living and the supernatural.

Police detectives Gatz and Rizzo investigate the case, suspecting Michael murdered his wife to marry Alison. They discover Brenner's stabbed body and contend that Alison herself might have killed Brenner. The investigation widens to include possible supernatural elements.

Investigators learn that the people present at the cat's birthday party are in fact deceased murderers. The party becomes a terrifying reveal of past crimes and present danger. The revelation unsettles everyone involved and deepens the mystery surrounding the brownstone.

Alison seeks solace in a Catholic church, confessing her sins, including adultery with Michael, to Monsignor Franchino. The act binds her more deeply to the church and foreshadows a larger cosmic order at play. The confession hints at a hidden truth about the building and its occupants.

Michael breaks into the Diocesan office and reads Halliran's file, which reveals a pattern of suicides linked to the clergy's past. He learns that Alison is slated to become Sister Teresa the next day. The discovery heightens his fear and desperation.

Frightened, Michael confronts Halliran, who reveals that the brownstone is the gateway to Hell. Michael attempts to strangle Halliran, but is killed by Monsignor Franchino. The supernatural danger closes in on Alison and the building.

In the brownstone, Chazen and the minions of Hell reveal that Halliran is the Sentinel who prevents demons from escaping. The now-deceased Michael is revealed to have hired Brenner to kill his wife, tying the human affairs to the demonic scheme. The living and the dead are drawn into a singular, perilous conspiracy.

Halliran's struggle with the demons indicates that Alison, given her history of suicide attempts, has been chosen as the new Sentinel to save her own soul. Chazen tries to persuade her to join Michael in Hell. The weight of destiny rests on her decision.

After a fierce internal battle, Alison takes the cross from Halliran and accepts her role as Sentinel. She rejects Michael's lure and commits to closing the gateway to Hell. The decisive moment marks the turning point in her fate.

The brownstone is demolished and replaced with a modern apartment complex. Miss Logan continues to show units, telling a young couple there are two neighbors: a violinist and a reclusive nun. Alison, now blind and dressed as a nun, sits at the top window, watching over the new residents and the city.