When we first meet Ben, he's trying a case for a Black woman named Gracie who is accused of murder. He thinks the only reason she's found guilty of the crime is because of her skin color, but he's in for a surprise: Gracie really did it. She thanks him for trying her case anyway, and hugs him goodbye.
When Ben gets home that night, his wife is acting strange. She tells him that they're growing apart and she's sick of waiting around for him. She gets why he wants to use his Harvard law degree to stand up for people no one else will, but those cases don't make money, plus she wants him to take more of an interest at home with her and their two daughters.
It turns out Ben can't do this, though, because he's been sent on a top-secret mission to Eudora, Mississippi for President Roosevelt. His old army buddy wants him to investigate reports of lynching; he's not sure whom to believe, and he needs Ben to report back to him with the truth. Of course Ben says yes to the mission—you don't really say no to the president—but he's also interested in finding out what's happening back home. He's from Eudora, and his cover story is that he's interviewing some judges while he's down there.
Ben's first stop back home is his dad's house. The guy is a well-respected judge in town, but Ben doesn't care for him much and they don't really see eye-to-eye. After a painfully awkward meeting with his dad, Ben gets down to business. He catches up with some old pals like Jacob, L.J., and his first love, Elizabeth, going to some dinner parties along the way. President Roosevelt gave him the name of someone in the Quarter who can help him out, so Ben pays him a visit, too.
The guy's name is Abraham, and he's as friendly as they come. Right away, the two strike up a friendship. Ben knows he can trust Abraham, so when his new friend takes him to several lynching trees, he figures out Eudora is being torn apart. In fact, he even hears about several lynchings while down there—and when he tries to stop them, Ben is attacked and lynched himself. He almost dies, but Abraham and his family nurse Ben back to health.
By the time Ben is back on his feet, everyone in town knows about his scuffle with the mob. Here's the thing: No one cares very much. Everyone wants to leave things well enough alone, even some of his old friends. Ben goes to stay with his childhood BFF, Jacob, for a while, but stops after the guy takes him to a Ku Klux Klan meeting one night. It seems like everyone in town, from the police chief to the local doctor, is part of the KKK. Yikes. Next Ben stays with his buddy L.J. who isn't a KKK member and is willing to help his friend out. Phew.
It turns out that L.J. is willing to put his money where his mouth is, too: He hires protection for Ben to stop the White Raiders from hunting him down again. When Ben hears that Abraham's family is in trouble, he and L.J. head over there to protect them. Things go from bad to worse when the White Raiders show up, guns in hand—there's a scuffle and two people die.
Normally this sort of thing would get swept under the rug in Eudora, but L.J. convinces the police chief he has to make an arrest because the men killed two people for no reason. Luckily, the chief listens and throws some of the White Raiders in jail.
Ben knows that the trial won't be a fair one, though, especially when his dad is appointed the judge over the case. He helps the other lawyer assigned to the case (a dude named Jonah) argue against the White Raiders, but it's of no use and the men get off scot-free. Again. Ben is frustrated, and decides to make a big statement to the whole town. He visits Abraham one last time before his old, sick friend dies.
Then he asks Abraham's granddaughter, Moody, if she'd like to hold his hand walking down the street. Since Moody is Black and Ben is white, this is a big deal in this neighborhood—everyone stares at them, and some people even spit or threaten worse. Ben kisses Moody and then they run back to the Quarter. They tell everyone to get ready for the White Raiders to show up again that evening.
And show up, they do. The White Raiders enter the Quarter mighty and proud, only to be taken down a peg or two by the Black people in the Quarter. Ben has the chance to kill Jacob and some of the other White Raiders, but he doesn't because he doesn't know how he'd live with himself if he did. Instead he goes back to Washington, D.C. to be with his family. Luckily, his wife Meg has reconsidered leaving him, and he promises he won't go anywhere either.