Investigator Troy Dunn has an impressive track record for locating people, from finding birth parents to organ donors. In 1990, Dunn helped his own mother (who was adopted as a baby) locate her biological family, and that single event inspired him and his then-business partner to build an organization that did one thing: help people reunite with long-lost friends and family members. APB with Troy Dunn documents the work he does, which was previously filmed for WE TV's five-season run of The Locator. A more modern twist in APB, however, allows TNT viewers to use a social media app to contribute to Dunn's mission of bringing families and loved ones back together.