San Francisco, September 1921: Silent-screen comedy star Roscoe "Fatty" Arbuckle is throwing a wild party in his suite at the St. Francis Hotel-girls, jazz, bootleg hooch...and a dead actress named Virginia Rappe.

The D.A. says it was Arbuckle who killed her- crushed her under his weight-and brings him up on manslaughter charges. William Randolph Hearst's newspapers stir up the public and demand a guilty verdict.

In desperation, Arbuckle's defense team hires an operative from the famed Pinkerton detective agency to investigate and, they hope, discover the truth. The agent's name is Dashiell Hammett... and what he discovers will change American legal history-and his own life- forever