LARK (17), an idealistic righter of wrongs, is still guilt ridden by the death of her father a few years earlier. When she stumbles upon a threatening exchange in an online chat forum, she connects it to the brutal murder of a young woman. With strong suspicions, but little evidence, Lark decides that the only way to draw the violent killer out is to make personal contact with him online using a false identity. But what starts out as a simple, clever strategy from the safe distance of social media ends in unforeseen, terrifying complications, leading to the unmasking of her identity by the killer. Now, with the help of some unlikely allies, Lark is forced to take matters in her own hands... before becoming the next victim of the ruthless killer.