Janitor Xu Jianxia solves a math problem and joins a top high school. She seeks her father, but finds he has remarried—his daughter, Xu Nanjiao, is her age. Xu Nanjiao bullies her relentlessly. They bet on who tops the exam; the loser must kowtow 100 times. Xu Nanjiao scores 690, but Xu Jianxia's...
