It's 1983 and Hector Negron (LAZ ALONSO) is not far from retirement working for the postal service in New York City. Yet, when he recognizes a man from his past, he shoots the man dead with an old German Luger. Rookie reporter Tim Boyle (JOSEPH GORDON-LEVITT) shows up late on the scene, but manages to convince NYPD Detective Antonio 'Tony' Ricci (JOHN TURTURRO) to let him accompany two other cops to check out Negron's apartment. There, they find the head of a 450-year-old statue that's been missing from Italy since 1944.
We then flash back to that year when Negron, a Puerto Rican, along with 2nd Staff Sergeant Aubrey Stamps (DEREK LUKE), Sergeant Bishop Cummings (MICHAEL EALY) and Private First Class Sam Train (OMAR BENSON MILLER) are members of the 92nd Infantry division, a.k.a. the Buffalo soldiers, patrolling in Tuscany, Italy. Due to a surprise German attack and the ineptitude of their white commanding officer, Captain Nokes (WALTON GOGGINS), they end up cut off from the rest of their regiment.
To complicate matters, the gargantuan Train rescues a local orphan boy, Angelo Torancelli (MATTEO SCIABORDI), and refuses to give him up, even after they encounter some friendlies in a nearby villa. Although the gruff but proud fascist Ludovico (OMERO ANTONUTTI) isn't happy to see them, his adult daughter Renata (VALENTINA CERVI) is more accommodating.
Even so, they worry about the place being surrounded by German soldiers who are not only after one of their own, Hans Brundt (JAN POHL), who's gone AWOL, but also the band of guerilla fighters, led by Peppi "The Great Butterfly" Grotta (PIERFRANCESCO FAVINO) and his right-hand man, Rodolfo (SERGIO ALBELLI), who are constantly ambushing the Nazis.
From that point on and as Angelo becomes increasingly distressed by the arrival of Peppi and his men who've captured Brundt, the American soldiers must not only contend with their perilous situation, but also that they're part of a black unit that's fighting for a country where they don't have any civil rights.