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HBO The Undoing Ending Explained – Different From Book

HBO The Undoing is loosely based off of the Jean Hanff Korelitz’s book “You Should Have Known.” The series is a bit different from the book, check them and and the ending explained.

HBO The Undoing Ending Explained

The finale of HBO The Undoing aired Sunday, revealing some real bomb shells, including who murdered Elena Alves. The series left audiences on a cliffhanger at the end of each episode with different potential suspects given, including Grace, her son Henry and her father Franklin. Sunday we were given some answers, so lets go over the ending explained and compare how it’s different from the book.

The Undoing Parents Guide Review

HBO The Undoing Quotes

The Undoing Ending Explained


Grace finds the murder weapon hidden in Henry’s violin case. When questioned further, Henry admits he found the weapon at the family home, where Jonathan had escaped to and eventually arrested by the police.  Henry admits to running the weapon through the dishwasher, twice, to remove all evidence. It seems like Grace is still ready to stand by Jonathan, until he flips the script and starts to suggest it was Henry who murdered Elena.

Grace calls Sylvia and the two have a secret chat, never revealing the details of the chat to audiences. After this, Grace volunteers to go on the stand to defend Jonathan and speak her truth. Sylvia also happens to meet the prosecuter in the bathroom, but it is never revealed what they spoke about either.

Grace takes the stand, defending Jonathan, until she is cross examined and it becomes clear Grace set Jonathan up. The meeting with Sylvia, Sylvia’s meeting in the bathroom and her volunteering to testify for Jonathan all come together as Grace takes the stand and reveals what Jonathan’s mother has said about him and the death of his little sister, that he is incapable of remorse. Haley and Jonathan become outraged at Grace’s testimony and tries to call for a mistrial, but they are unable to because she was their witness.

Grace’s testimony assumes that Jonathan is the killer but nothing is verified until the next day, when Jonathan texts Henry to join him for breakfast. Jonathan basically kidnaps Henry in his vehicle, police find him and follow the two. As they are driving Jonathan begins to have flashbacks of the night of the murder, these flashbacks show him killing Elena. He also pretty much confesses to Henry that he “lost control” and was Elena’s killer.

It ends with Jonathan driving to a bridge and trying to jump off it as Henry holds him back. Grace arrives and runs toward the two, grabs Henry and runs off, leaving Jonathan behind. The police swoop in and arrest Jonathan.

The Undoing Ending Explained Different From Book

How Is The Undoing Different From The Book?

The Undoing follows the same concept as it did in the book but there are some major differences.  First, Jonathan is never shown in the book. It is always assumed that he is the killer, he even confesses to the killing in a letter he leaves for Grace.

Elena’s name in the book is Malaga and unlike the series, where she is bludgeoned to death with a hammer, in the book she is stabbed to death.  The series does not really reveal the reason Jonathan kills her, he just sort of snaps and hits her repeatedly with the hammer. In the book however, she reveals that she is pregnant a second time with his child and that is the reason he murders her.

Since Jonathan never really makes an appearance in the book, there is also no trial and therefore no attorney representing him. His attorney Haley is not in the book and a new character added to the series.

One difference I found particularly interesting was the death of his sister, Katie.  The story in the book was much of the same, in regards to him accidently killing his family dog, later to be revealed it was really his sister.  In the book however, it is Jonathan’s mother that reveals the sibling death to Grace.  And it was not a sister who was hit by a car but rather Jonathan’ brother who was left in his care because he had the flu. Jonathan killed his brother by leaving him outside in the cold until he got sicker and sicker and eventually died.

The Undoing Ending Explained - Different From Book