S1, E15: When Bull assists the U.S. Attorney's Office with a manslaughter trial against a real estate magnate, Andrew Withrow (Toby Leonard Moore), he finds himself once again opposing Diana Lindsay (Jill Flint), his romantic rival. As the case gets underway, Bull's penchant for winning goes into overdrive when he realizes the defendant is a clinical sociopath determined to use Diana to antagonize him during the proceedings.