HBO's The Undoing is basically one twist after another. In the premiere episode of the six-part miniseries, Elena Alves (Matilda De Angelis) is brutally murdered, and now it looks like Jonathan Fraser (Hugh Grant) may be responsible for her death. Not only that, but it turns out, he's the father of her newborn daughter.
If you've read Jean Hanff Korelitz's You Should Have Known, the novel on which the show is based, then you probably already knew that Jonathan was the father. In the second episode, we find out that Jonathan was secretly having an affair with Elena prior to her death, and Elena's husband, Fernando Alves (Ismael Cruz Córdova), demanded a paternity test, insisting to police that he's not the father of Elena's baby. Shortly after, we see Grace Fraser (Nicole Kidman) having visions of Jonathan and Elena having sex, which was probably writer David E. Kelley's way of subtly confirming that Jonathan is the father, because by episode three, the DNA results come back proving that he is.
The news of Jonathan and Elena's affair explains why Elena was particularly taken by Grace when they first met; however, we're still left wondering who killed Elena. With three episodes left, hopefully we'll get some answers soon!