Ted goes out for a crazy St. Patrick's Day with Barney, and discovers how much he's changed. After Ted has what he considers the most legendary night, Marshall replays the messages Ted left on his voice mail when his cell phone accidentally pocket dialed, and after hearing snippets over the course of the night Ted ultimately realizes he was acting like a jerk and he doesn't want to be that guy. Also, Marshall, Lily and Robin spend the night in Marshall and Lily's new apartment, only to make their own shocking discovery that the apartment is crooked.