It was the beginning of summer break. Shawn and Sara were excited about their trip to stay with their older sister, Amie for a few weeks. Shawn and Sara were 16-year-old twins, and had just finished their sophomore year of high school. Amie was a 24-year-old fitness instructor and amateur model. The twins had not seen their older sister since she had left home a year earlier to start her modeling career in San Diego. The...