Bolingbroke and many nobles assemble for Parliament at Westminster Hall in London. Bolingbroke calls Bagot as a witness and asks him what he knows about the murder of Gloucester. Bolingbroke implies that Richard and others were responsible. Bagot accuses Aumerle of being involved in the plot against Gloucester. Aumerle denies it and says Bagot is lying. He challenges Bagot to combat, but Bolingbroke forbids Bagot to respond to the challenge.

Fitzwater then testifies that he heard Aumerle say that he was the cause of Gloucester’s death. Aumerle is defiant, saying that Fitzwater is damned for his false accusation, but Percy accuses Aumerle of lying about Fitzwater and challenges him. Another lord accuses Aumerle and challenges him. Surrey intervenes and says Fitzwater is lying and challenges him. Fitzwater, in his turn, insists that Aumerle is guilty of Gloucester’s murder; he says he himself heard Mowbray say that Aumerle sent two of his men to murder the duke at Calais. Aumerle says that Mowbray lied, and he wants to challenge him. Bolingbroke rules that the challenge must be put off until Mowbray returns, since Bolingbroke intends to repeal his banishment and restore his confiscated lands. However, Carlisle says that Mowbray has died in exile in Venice.