Florence Pugh in “A Good Person.” Metro Goldwyn Mayer Pictures

Taking on such hot topics as distracted driving, substance abuse and teen pregnancy, “A Good Person” plays like a two-hour public service announcement.

In this wildly uneven melodrama by writer-director Zach Braff, no member of the talented ensemble cast is entirely able to navigate its messy plot. That a few actors do manage to stay afloat for occasional breaths of air seems like a divine miracle. But for much of the film, God is not in the details.

This would-be three-hankie tear-jerker follows the travails of Allison (Florence Pugh), an obnoxious 20-something who’s on her way to pick out a wedding dress when she causes a car accident that kills two people, including her fiance’s sister Molly. The crash has other shattering repercussions: Molly’s father (Morgan Freeman) has to take care of his now-orphaned granddaughter, Ryan (Celeste O’Connor). Can the frayed ends of this broken family ever be mended?

The film’s fraught, tangled relationships are supposed to mirror real life. But Braff writes his characters into too many impossible situations, gently presided over by Freeman, whose introductory voice-over notes that, unlike the model train set he’s built in his basement, we can’t control the tracks of our lives.

As the story goes on, you might find yourself wishing that this train wreck came with fewer track switches. “A Good Person” fails in both writing and direction.

Florence Pugh, left, and Morgan Freeman in “A Good Person.” Jeong Park/Metro Goldwyn Mayer Pictures

Braff, whose last feature was the slight 2017 comedy “Going in Style” – also starring Freeman – gets lost in his own storyline, frequently letting his actors flail away without focus. As Allison descends into OxyContin addiction and Ryan shifts from model student to troubled teen, their emotions get lost as the filmmaker pushes Pugh and O’Connor to serve up increasingly high-pitched, Oscar-bait-y performances.

There are entire scenes that beg to be cut. (Here’s a suggestion: How about the whole first half hour?) As soon as we meet Allison, she’s grating, delivering a smarmy rendition of the Velvet Underground ballad “After Hours.” (Turns out to be appropriate, given the character’s downturn.) There’s also a completely unbelievable scene in which Allison goes slumming in a dive bar, only to run into a couple of old high school classmates eager to take their revenge on the once-popular girl who used to ignore them but now wants their drugs.

Things eventually calm down, thanks largely to Freeman, who tempers his castmates’ youthful excesses with the quiet wisdom of age. To her credit, Pugh manages to evince some restraint. It’s in these quiet moments that her talent shines.

Still, Freeman is the only performer here who doesn’t overact. You can almost picture him saying no, politely, when Braff urged him to push the limits of decorum: “Son, I will give this silly line of yours the only reading that could lend it the slightest bit of credibility.”

Just like that fateful car accident, however, “A Good Person” violently careens out of control. For the most part, it means well, and underneath all the sensationalism, there’s a valuable message of forgiveness and redemption, albeit one with a caveat: Easier said than done.

It almost – almost – made me wonder something: Am I a bad person, for not liking it?