Casey Affleck (left) and Lucas Hedges in “Manchester By the Sea”PHOTO: CLAIRE FOLGER / COURTESY OF AMAZON STUDIOS AND ROADSIDE ATTRACTIONS

Early on in writer-director Kenneth Lonergan’s superb Manchester By the Sea, there’s a flashback to a moment of pure innocence and fun — to better days — for the film’s two main characters. During a carefree fishing expedition, Lee Chandler (Casey Affleck) asks his young nephew Patrick (played at this point by Ben O’Brien) one of those leading “what if” questions: If you were stranded on an island and could choose only one person as your companion, the kind of person who would be able to keep his head and solve any problem that might arise, who would you choose? The playfully loaded question offers a choice between Lee himself and Patrick’s father Joe (Kyle Chandler), who is also Lee’s older brother and happens to be in charge of the boat. 

The boy selects his father and accepts the good-natured ribbing from his uncle. The scene, unadorned by sentimental lighting or melodramatic musical cues, has the spot-on feel of an unforgettable memory that might stay with you until your dying day. Forget proof of life; this is undeniable proof of something far more elemental: love. 

Critics long for films with such gentle and lingering impressions; each screening offers a new opportunity to be engaged on this level. I caught Manchester By the Sea on the first day of the Toronto International Film Festival; in fact, it was the very first screening I attended and it set a distinctive high-water mark. 

Lonergan gradually dampens the warm enveloping sensation of that blanket of love, and then peels away layer after layer from Lee. We see him in the present, alone, working anonymously as a facilities manager, shoveling snow and tending to the plumbing needs of apartment dwellers. He’s handy and good-looking in a quietly rugged way, so he attracts the attention of female tenants, but it is obviously unwanted. The love he once had for his nephew, and by extension himself, is long gone. Lonergan teases us with more glimpses into Lee’s past, where he goofed around with his wife Randi (Michelle Williams) and his own children. They may not have had much, materially speaking, but again, there was evidence of an abundance of this carefree love.

And then, again in the present, Lee gets the news that his brother Joe has died, which draws him back home to Manchester, Mass., where apparently everything that was good in Lee’s life was lost. He returns, ready and willing to do right by his brother, to make all of the necessary arrangements for his burial, and then beat another hasty retreat away from his buried pain. Everyone in town seems to lurk a safe distance away, watching and whispering about Lee, aware of his tragic past. 

The reading of Joe’s will forces Lee to recall that moment on the boat. He’s been tapped by his brother to become the guardian of the now-teenaged Patrick (Lucas Hedges), a spirited and headstrong kid with a life in Manchester he has no desire to leave. 

In a different film, the broadly scripted banter between Lee and his nephew would have, all too plainly, set the stage for some raucous sitcom-inspired conflict before settling down for a predictably heartwarming happy ending. Said iteration might have also given Lee a second shot at love in the form of a sassily sexy mother of one of Patrick’s friends. Of course, such a film would not have been written or directed by Lonergan, an accomplished playwright whose films (You Can Count on Me and Margaret) also have been highly praised. Nor would such a film have featured Affleck as Lee.

How can I describe what Affleck brings to the character of Lee Chandler? To start, unlike his famous brother Ben, Casey Affleck is not a star of either the tabloids or conventional studio movies. He is far removed from the hero worship heaped upon the personalities that dominate entertainment news.

He is more of a character actor. On a deeper level, that label means he is free to disappear in the method antics necessary for a role like this. We never self-consciously catch ourselves “watching” him act. Affleck lives in every frame, carrying Manchester By the Sea along with him, toward a transcendent state of being that reminds us of our own moments of love irretrievably lost. (Opens Friday at the Esquire Theatre) (R) Grade: A