In the thriller series The Better Sister on Prime Video, Jessica Biel and Elizabeth Banks star as sisters who are driven apart by a man (played by Corey Stoll) but find themselves reunited following his murder. Throughout the eight-episode series, viewers are led down a suspenseful trail where distinctions between love and hate become unclear, and questions about guilt and innocence arise.

Ultimately, just one individual is behind Adam’s (Stoll) death, and the revelation of this killer might surprise those who believe they’ve unraveled the mystery. Continue reading for a detailed overview of the Season 1 finale of The Better Sister.

**Spoilers for The Better Sister, now streaming on Prime Video**

In this intricate narrative, the list of suspects includes Chloe (Biel), who was Adam’s wife at the time he was killed, and Nicky (Banks), the sister who has a child with him. Did one of them lose control? Or could it be their now teenage son (Maxwell Acee Donovan), who connects all three and had motivation to resent his father? So, who took the final step, and how did they manage it? Here’s a concise breakdown of the Season 1 finale of The Better Sister.

The Better Sister Ending Explained:

In the end, as many may have predicted, it was one of the two sisters who killed Adam as he had shown signs of abuse toward both Nicky and Chloe. Most recently, Ethan (Donovan) watched as Adam aggressed Chloe in the middle of an argument, grabbing her and throwing her into a wall as Ethan witnessed the entire encounter from the balcony where his dad and stepmom could not see him.

From there, Ethan told his biological mom, Nicky, via his secret burner phone about the incident, which is when she decided to step in and do something about it. In the Season 1 finale, “They’re In Their World,” we see Nicky show up at Adam and Chloe’s beach home to try and help her sister leave Adam, only for him to attack her. As they argue about Adam hurting her sister and framing Nicky for nearly killing their son, we find out he drugged Nicky and nearly let her drown when they were still together so he could strip her of her parental rights.

During their fight, Nicky manages to pull out a switchblade from her pocket which is how she stabbed Adam several times, leaving his body on the floor and fleeing the scene with the knife still in hand. What we didn’t know until the finale is that Ethan, not Chloe, was the first person to find Adam’s body after the murder, but that he did nothing to help his dad knowing that his mom could look guilty. He ultimately opted to leave the house and not call for help, knowing that paramedics may save his dad and the blame could fall on his mom or his stepmom.

At the beginning of the finale, Nicky explains all of this to Chloe, which is when Chloe decides she will help to cover her sister’s tracks, choosing to frame Bill Braddock (Matthew Modine) for her husband’s murder. Chloe slyly slips the switchblade used to kill Adam into Bill’s desk during a trip to his home after finding out that Bill — one of the founding partners at Adam’s law firm — was involved in shady business dealings and human trafficking. It’s during this visit she plants the murder weapon in his desk and leads investigators to information suggesting he killed Adam to cover up his own crimes.

Meanwhile, Detective Nan Guidry (Kim Dickens) manages to put together the pieces and figure out that while Bill looks incredibly guilty, Chloe is actually the one who murdered Adam as she knew his manner of death before police released that info. Chloe had told Adam’s mother (Deirdre O’Connell) that her son was dead before anyone had confirmed that news to her, meaning that she either was responsible for the killing or knew someone who was.

Before Nan can arrest Chloe, however, the sisters leak Nan’s history of police brutality and the cover-up from her superiors, which prompts her own captain to put her on suspension, essentially putting the kibosh on her investigation up to that point.. Additionally, because they have arrested Bill by that time, the captain decides to forego the information on Chloe’s motive and opportunity that Nan had gathered, putting the case to rest.

The show ultimately ends with the sisters finally coming back together having framed Bill for Adam’s murder and reestablishing their family unit with Ethan. They promise to never let themselves be separated again and to reshape their lives together with one another at the center. That’s what you get for trying to get in the middle of sisters, Adam.

All eight episodes of The Better Sister are currently streaming on Prime Video.