It's 1914, Mike's dad met and married a nice black woman who has a half-white son named Alastor. Mike is 14, and taller than alastor as well as stronger. He doesn't like Alastor at all.

(Basically he's a mix of the cliches: step sibling bully and the bully you'd see in a typical high school movie, but with an added layer of sadism)