Dominic Cooper's New Romance Film Is the Polar Opposite of 'Mamma Mia' in This Sneak Peek [Exclusive]

The life of a lighthouse keeper was truly a lonely and grueling one. While few such beacons nowadays are run by a human crew, those who once manned the light for the safety of others did so at the cost of regular human companionship, often living in or near their place of work, sometimes without their families if they had one. Such is true for Seamus Óg MacGrianna, a keeper on the Irish coast in 1924, played by Mamma Mia! star Dominic Cooper in the new romantic drama The Lightkeeper. Seamus has been working in the lighthouse for years and has established a routine that keeps him tethered tightly to the past, but that's about to change with three very different people resolving to make him confront everything he's left behind.

The Lightkeeper follows Seamus as he goes about his carefully planned days, tending to the garden of his former home and rowing out amid the morning mist to listen for the call of the Each-Uisce, which he hopes may set him free. Ironically, although he guides ships by night with the glow of his lantern out to sea, he's lost in a listless existence during the day until various other lives begin intersecting with his. From a mysterious American widow seeking closure and igniting a new spark in his life to a hard-line priest determined to pick a fight of wills with the stubborn keeper, the walls he's erected slowly begin to crumble. However, ahead of the film's premiere at the Hamptons International Film Festival this afternoon, Collider can exclusively share a new sneak peek highlighting Seamus' relationship with the third individual — his dedicated housekeeper, Maire (Sarah Bolger).

The video opens with Maire walking to the lighthouse on a dreary day and finishing up a few chores before she leaves. When she goes to find the keeper to tell Seamus she's done, however, she catches him asleep atop the beacon, where he's in the middle of a haunting dream of someone drowning deep underwater. Upon waking him up, she rushes him to hurry and catch the ferry to the mainland, though on her way out, she eyes a photo of what appears to be the man in his childhood alongside other mementos of his past. Every shot serves to establish the cold and gray atmosphere of Seamus' mostly dull world, save for the warmth of Maire, who looks out for him, down to insisting he take his scarf for the cold boat ride. For as wordless as he is, even he can't help but assure her he'll be back in time for dinner. Otherwise, he carries himself with a quiet intensity, going through the motions even as others try to breathe life into him.

Who Else is Behind 'The Lightkeeper'?

Previously starring in FX's Mayans M.C. and, more recently, the MGM+ crime drama The Westies, Bolger plays one of the few unconditional forces in Seamus' world, giving the energy of a genuine caretaker looking out for the troubled man. Their relationship will be at the heart of the film as it becomes clear that even her warmth might not be enough to save the lighthouse keeper from himself. Joining the duo are Sarah Gadon as the American widow Edith and Aidan Quinn as Father MacGabhann. Emmy winner Vic Sarin, who was last seen helming the crime feature Sugar with Katherine McNamara and Jasmine Sky Sarin, directed from a screenplay by Ciaran Creagh.

The Lightkeeper premieres at HIFF in East Hampton, New York, later today. Check out our exclusive sneak peek in the player above.