After conning his way (with the help of a "Possession" vigor) into a restricted area and meeting a strange man and woman who ask him to call a coin flip and then wander away, Booker has his first real shock since arriving in Columbia. A sign in front of him warns the God-fearing citizens of the city to beware the false shepherd, whom they'll know by his mark: the letters "AD" scratched into the back of his hand. Sure enough, there they are on Booker's right hand. Things get tense after this.
You'll make your way to a grand stand, where a raffle is being held. An earlier telegram (odd, how does anyone know Booker's there?) warned you not to pick number 77, but unfortunately Booker seems to have forgotten about this. So he picks number 77, of course, and guess what? It's his lucky day.
What happens next proved nothing less than shocking. The announcer on stage makes a slightly racist comment; it seems strange enough. But then a black woman and a white man—an interracial couple—is led onto the stage in bonds, and you're told that Booker's winning the raffle gives him the right to throw the first "stone" (in this case a baseball). Yup, it's a good old-fashioned racist stoning. Holy shit.