When her friends gift her a 23-and-Me test as a gag, high school senior Chloe Kang doesn’t think much of trying it out. She doesn’t believe anything will come of it—she’s an only child, her mother is an orphan, and her father died in Seoul before she was even born, and before her mother moved to Oklahoma. It’s been just Chloe and her mom her whole life. But the DNA test reveals someth…