Plot summary
Henry reveals he found the hammer in the fireplace at the family beach house and hid it to keep his father from being arrested. During the trial, Jonathan gives his testimony, admitting his infidelity, but insisting his innocence over Elena's murder. Haley brings Miguel to the stand, where Miguel suggests Fernando had been abusive towards Elena. Grace requests to take the stand and after claiming Jonathan to be a person of empathy, the prosecutor gets her to reveal her conversation with his mother. Jonathan and Haley realize Grace asked to take the stand as a ploy to allow her to suggest her belief in Jonathan's guilt.
With Jonathan's conviction all but guaranteed, he asks Henry to breakfast before the verdict, only for it to be a ruse for Jonathan to escape with Henry. Flashbacks reveal Jonathan murdered Elena after ordering her to stay away from his family. After being chased by police and almost getting hit by a truck, Jonathan threatens to jump off a bridge and commit suicide. Grace arrives via helicopter to rescue Henry and the police arrest Jonathan.
Credits
Adapted from Wikipedia contributors, The Undoing. Series, exact episode number and English title matched. Paragraphs formatted; references and illustrations omitted.