The dynamics between fathers and sons, and whether the younger generation can ever escape the family legacy, is at the heart of “Devil’s Peak.” It’s apt then that director Ben Young cast Hopper Penn — son of Sean — as his lead. In this adaptation of David Joy’s novel “Where All Light Tends to Go,” the father, Charlie (Billy Bob Thornton), is a drug lord in North Carolina’s Appalachian Mountains, with a firm grip on his son’s life and livelihood. Jacob (Penn) works as a runner for his dad, while the latter withholds his wages, thus totally controlling his son. Young and screenwriter Robert Knott build on these intriguing family dynamics to create an entertaining drama that’s unfortunately let down by its lead performance.

The conflict between father and son takes hold when Jacob falls for a local woman (Katelyn Nacon) at the same time that Charlie becomes the target of her DA stepfather (Brian d’Arcy James). The standoff between the adults forces Jacob to consider leaving town and confronting his father about his money. In persuading Jacob to stay, Charlie spins a good yarn about their home and business being Jacob’s unescapable legacy. The tale he tells, with shades of Greek tragedy, puts a magisterial sheen on “Devil’s Peak,” taking it beyond a garden variety B-movie.

Charlie tells stories to intimidate, cajole and seduce those around them. Knott’s screenplay affords Thornton lots of leeway by giving him long monologues that he gnaws on with relish. Fleshing out what might have otherwise been a stock antagonist character, Thornton gives his patriarch eccentric edges. This manifests particularly in his interactions with Emma Booth, who plays his younger wife. Theirs is a robustly sensual relationship that teeters on the edge of kink. Nothing is shown beyond a bitten lip dripping blood, but Thornton and Booth telegraph much while playing off of one another. Thornton is never less than fascinating and the film becomes captivating when the focus is on him.

As Jacob’s drug-addicted mother, Robin Wright dims the hauteur she has displayed on Netflix’s “House of Cards.” Donning dull brown hair and teeth painted to look dirty, she gives her character authentic regret as a woman who knows she has wasted her life. Her dedication — she’s also a producer on the film — belies her belief in this story. Alas, she’s paired mostly with her real-life son Penn as Jacob, and the younger actor proves unable to match her.

With Jacob at the center of the film’s narrative, Penn is given ample screen time and copious close-ups, but he doesn’t rise to meet this opportunity. Jacob is falling in love while trying to break free from his father. He also tries to maintain a connection with a mother who’s not altogether there. Throughout all these emotionally taxing beats, Penn hardly varies his reactions, no matter the actor he’s playing with or the circumstances his character is navigating. It’s all delivered with the same semi-fearful, semi-concerned facial expression. Young resorts to using slow-motion and ominous music to try and hide the inadequacy of this performance.

Knott’s script can also be funny at times, as when it tells a joke about a misspelled tattoo. The situation is funny, but the scene says more than just that. It evokes the places these characters inhabit and the people they interact with. Young has a keen sense of place, and his cast, which also includes Jackie Earle Haley, gives the film a sense of gritty reality.

Despite some good performances and vividly written characters, “Devil’s Peak” crumbles due to Penn’s inexperienced performance. Otherwise, it’s an entertaining drama with some grandiose ideas about family legacy that make it peculiarly compelling.