It’s not “Flowers in the Attic,” but watching two siblings trifle with one…

It’s not “Flowers in the Attic,” but watching two siblings trifle with one another still makes audience members squirm.

When one sibling unknowingly flirted with another — who was aware of their familial relationship — for more than an hour, the audience verbalized their discomfort. And that little dance goes on far too long, punctuating “People Like Us,” an otherwise excellent movie, with spectacular moments of awkwardness.

It begins when Sam (Chris Pine), deep in debt, finds out his record executive father has died and is summoned from his adult life in New York to attend the funeral in Los Angeles. There, his dad’s lawyer gives him $150,000 to deliver to a half-sister he’s never met, Frankie (Elizabeth Banks).

Here begins his pseudo-stalking, where he purposely runs into her at AA and learns about her grim perspective on their father. And then he runs into her over and over again until they eventually befriend one another.

He begins helping out with her bright, but troubled, son, Josh (Michael Hall D’Addario), and hanging around with the pair for weeks, even extending his hometown visit in Los Angeles to stay with them. All the while, Sam works to uncover why his father abandoned his sister and her mother.

As Josh becomes more accustomed to Sam’s presence and Frankie starts hinting at a romantic relationship, Sam realizes he has to come clean, a confession that could ruin his relationship with both of them.

The movie lets Sam keep Frankie in the dark too long. Maybe it speaks to the talent of the actors that they could elicit a response from viewers, but nearly a half-hour before Sam’s reveal, the audience started shifting, muttering and otherwise expressing that they wanted him to just tell her already.

But there were many bright spots in the movie to make up for that.

The actual story is riveting, exploring family relationships, the lies parents keep and the moment when children recognize and forgive their parents’ imperfections. It’s uplifting in a way that isn’t cheesy. At the end of the movie, everyone’s lives are a little better, but there isn’t total resolve — these people will still have to live with their scars.

And much of these themes are to the credit of the actors.

Pine proves he has the chops to play the self-sacrificing Sam, who, while helping improve someone else’s life, is simultaneously destroying his own. Banks pulls off the pretty, but broken, child of an unpredictable father. Michelle Pfeiffer kills it as the mother of Sam and widow to his father — she makes you feel anger and sympathy toward her simultaneously.

And yet, there’s a reason the old adage exists that one should never share the stage with children or pets. D’Addario steals attention from everyone else. It certainly helps that he even charmed the movie’s cast. His portrayal of a precocious mischief-maker shines every time he appears on the screen — he’s just so darn lovable.

Potential incest aside, “People Like Us” has the actors and — for the most part — the heartwarming plot to develop a great movie.