Watch on HDtoday. Jenna returns to her job as a Boston 911 emergency dispatcher, where she's still haunted by the death of her teenage brother and the missed call he placed to her in his final moments. What begins as an ordinary overnight shift soon takes a turn when callers report strange incidents connected to a mysterious event in Boston Harbor. And as a threat closes in on the dispatch center itself, the film gives way to a chilling realization: Boston is ground zero for a catastrophe.