Don’t bother with your finale theories for The Undoing. The ending is almost “impossible” to guess, says Matilda De Angelis, who stars as Elena Alves in HBO’s thrilling new miniseries. Her character is violently killed in the first episode, but her demise is central to the show’s whole narrative.

For the past five weeks, viewers have been obsessing, speculating, and downright spiraling over the core mystery—who killed Elena?—only to get thrown off by new bombshells and plot twists with each episode. So far, Jonathan Fraser, played by Hugh Grant, is being tried for allegedly committing the crime. A married, wealthy child oncologist, he treated Elena’s son, and then also had an affair with her.