"The Gypsy and the Hobo" (Season 3, Episode 12) serves as a pivotal climax in Mad Men , featuring the long-awaited confrontation where Betty discovers Don's true identity as Dick Whitman. This episode dismantles the Drapers' marriage and Don's carefully constructed persona, forcing a moment of absolute vulnerability that changes the series' trajectory. For a detailed breakdown of this iconic episode, you can read the episode analysis on AMC's website.