Mark Whitacre, a rising executive at Archer Daniels Midland (ADM), becomes an informant for the FBI after supposedly discovering a price-fixing scheme within the company. Bolstered by a sense of self-importance and dreams of corporate glory, Whitacre enthusiastically records conversations and gathers evidence for agents Brian Shepard and Bob Herndon. Whitacre convinces himself that he is on the brink of exposing a massive global fraud that will elevate his position within ADM, while also fulfilling a moral duty to the public. As Whitacre's operation unfolds, he spins a narrative where he envisions himself as an undercover hero.

However, as the investigation progresses, Whitacre's behavior becomes more erratic and his credibility is questioned. The FBI agents start uncovering discrepancies in Whitacre's story, including inconsistencies in his accounting details and surprising revelations about his own activities within ADM. Whitacre's complex web of lies, aspirations, and impulsive decisions make the case increasingly difficult for the agents to navigate. The deeper the FBI delves into the case, the more they realize that Whitacre's own actions may be as convoluted and dubious as the company's alleged crimes, leading to unforeseen complications and a dramatic unraveling of events.