Holland March (Ryan Gosling) is a depressed, alcoholic, arguably suicidal, private detective. When a distressed woman claims to have seen her seemingly dead porn star niece, Holland is hired to find her. He believes this woman has mistaken a young girl named Amelia (Margaret Qualley) for her niece. Amelia, however, does not want to be found. She hires an "enforcer" named Jackson Healy (Russell Crowe) to ensure Holland leaves her alone.

The two come to blows and Holland, left with a broken arm, abruptly stops his search for Amelia. But when Jackson is attacked and warned about making deals with this mysterious Amelia, he smells something fishy and begins to believe she is part of a bigger plan. He then recruits Holland to help track her down, and along with Holland's pre-teen daughter Holly (Angourie Rice), the unlikely allies uncover a nationwide conspiracy that somehow links Amelia to a series of tragic deaths involving professionals in the porn industry.