It’s part comedy, part tragedy. It’s part road trip saga, part weird couple movie, and part Holocaust movie. What could have gone wrong?

Yeah, everything could have gone wrong. So the first miracle of “A Real Pain,” writer-director Jesse Eisenberg’s remarkably accomplished film about mismatched cousins ​​on a grim journey through Poland, is how it pulls off the trickiest of balancing acts.

That he does so while asking intriguing questions about the nature of pain – personal or universal, historical or contemporary – is all the more impressive. So does the fact that he puts in an Oscar-worthy performance.

This stunning performance comes from Kieran Culkin, and what’s striking is that it doesn’t overpower the rest of the ensemble. This is mostly a testament to the careful way in which Eisenberg, who plays in the less flashy role, constructed and paced his film. And as for Culkin, well, if you needed proof that his steamy, Emmy-winning work as the tension-tortured Roman Roy in Succession wasn’t a fluke, here it is.

The film, only Eisenberg’s second film, stems from a trip the “Social Network” star took about 20 years ago to Poland. There, he found the small house in which his aunt lived before the Holocaust uprooted the family. He wondered what his own life would have been like if World War II had never happened.

And it’s one of many conversations David (Eisenberg) and Benji (Culkin) have as they travel through Poland on a mission to visit the house where their recently deceased grandmother once lived. (Eisenberg used the exact same house, which shows how personal this film was to him.)

It is a poignant but also awkward reunion for the cousins, close in their childhood but who follow very different paths in their forties. David is the anxious but high-functioning type that actor Eisenberg excels at; he works in technology and lives with his wife and young son in Brooklyn. As for Benji, he lives in the northern part of the state and is largely undocked or undeveloped. He’s also a study in contrasts – the guy, David notes, who can light up a room when he walks in, then shit on everyone. The death of their grandmother, to whom Benji was close, took a toll on his mental health.

The cousins ​​meet for the first time at the New York airport. Before even going through security, Benji terrified David by informing him that he had picked up some really good weed for the trip. (Don’t worry, he mailed it to the hotel.)