In 1996, Karina Holmer left her small Swedish village of Skillingaryd to travel to Boston, Massachusetts. The 19-year-old had plans to work as an au pair with an American family who lived in an affluent neighbourhood called Dover. Karina settled in well with her host family: married couple Frank Rapp and Susan Nichter and their two young children. But just three months after arriving in Dover, Karina suddenly disappeared after a night out with friends...