In 1987, a geologist named Harlan Creed mapped an abandoned mine shaft in rural Montana and accidentally placed a murder weapon, a missing body, and an innocent man's conviction on the same page. Tonight, we examine how a single hand-drawn survey map — ignored for nineteen years, misfiled in a county land records office — became the most damning piece of evidence no one was looking for, and what it reveals about the way investigators decide, too early, that a case is already solved.