On April 1, 2006, 27-year-old medical student Brian Shaffer spent the evening with friends at the Ugly Tuna Saloona in Columbus, Ohio. Security cameras clearly recorded him entering the bar. Investigators have never found footage showing him leaving. Nearly two decades later, Brian remains missing. Brian Shaffer The case remains one of America's most discussed disappearance mysteries.

In this episode of Unsolved and Missing, we begin with Brian's last known night, the surveillance footage, and the question that refuses to disappear.

A camera saw him arrive.

Why didn't it see him leave?