Selling the Girl Next Door takes viewers into the world of underage American girls caught up in the violent sex trade. Thousands of girls under the age of 18 are ensnared into lives of prostitution annually, according to the National Center for Missing & Exploited Children. Many are runaways or “throwaways” trapped in “the oldest profession” by pimps who sell them using modern sales and marketing techniques, including online classified websites. In a year-long investigation, CNN correspondent Amber Lyon reveals the devastating realities of the business of underage sex — speaking to a young teen runaway sold online from a Las Vegas hotel, the men that obsessively seek Internet sex connections, and women long into careers as sex workers who were trafficked as teens or children. Along the way, Lyon interviews well-known brothel owner Dennis Hof. Hof’s sex workers describe their own dark pasts and the frightening underworld of underage sex trafficking. Lyon also goes undercover herself, posting an online ad, and taking calls from solicitors — and Internet pimps — to understand more about how girls are victimized by traffickers.