Twenty-one-year-old Vancouver student Elisa Lam was last heard from on January 31, 2013, after she checked into downtown L.A.'s Cecil Hotel - a 600-room building with a history of scandal and tragedy. The next day, Elisa vanished. A search of the hotel yielded nothing. More than a week later, complaints by guests of foul-smelling tap water led to a grim discovery: Elisa's nude body floating in a rooftop water tank. The only apparent clue was a disturbing surveillance video of Elisa, uploaded to YouTube in hopes of public assistance. As the eerie elevator video went viral, so did the questions of its tens of millions of viewers. Was Elisa's death caused by murder, suicide, or paranormal activity? Was it connected to the Cecil's sinister reputation? And in that video, what accounted for Elisa's strange behaviour?