The Better Sister ending explained: The shocking truth behind Adam¡¯s murder in Jessica Biel¡¯s thriller

When you dive into Prime Video¡¯s The Better Sister, get ready for a rollercoaster of drama, deceit, and one seriously tangled family web. The eight-episode thriller starring Jessica Biel and Elizabeth Banks hooks you with a gripping plot, two estranged sisters, Chloe and Nicky, reunited by the murder of Chloe¡¯s husband, Adam, who just so happens to be Nicky¡¯s ex and the father of her son Ethan. Talk about complicated family dinners.

The Better Sister | Credit: Prime Video

The Better Sister ending explained

At first glance, Ethan looks like the prime suspect. Arrested and put on trial, the teen carries the weight of suspicion, his DNA on Adam¡¯s body, no less. But things are never that simple in this thriller. Turns out, Ethan witnessed Adam abusing Chloe and, in a panic, tried to cover for her by messing up the crime scene to make it look like a robbery. So, no, Ethan did not kill his dad, but he certainly played a dramatic part.

The Better Sister | Credit: Prime Video

The plot thickens when Chloe takes the stand, revealing the dark secret of Adam¡¯s abusive nature. She even drags Jake, Adam¡¯s friend and her secret lover, into the mess, painting him as a possible culprit. Jake¡¯s falling out with the law firm and insider knowledge about shady dealings adds more fuel to the fire, shifting suspicion away from Ethan.

The Better Sister twist

Then, we get a huge twist: Adam framed Nicky in the past to strip her of custody of Ethan by drugging her and making her look like an unfit mother. Nicky¡¯s tragic backstory and fight for her son add emotional depth that hits hard.

I¡¯m starting The Better Sister and the first point I¡¯d like to make is that Jess Biel¡¯s back makes me want to put down my chips and have an apple or something. Jesus Christ. pic.twitter.com/aWdTIw38JP

¡ª The Crimson Lights Puppet (@CrimsonPuppet) May 30, 2025

The climax? A showdown where Nicky confronts Adam after learning about the abuse. In a physical altercation, she stabs him fatally. The sisters then hatch a plan to pin Adam¡¯s murder on Bill, a crooked law firm partner with plenty of shady secrets, a perfect scapegoat.

But the drama is not over. Jake¡¯s mysterious death on the beach in the finale leaves viewers with unanswered questions: was it suicide or foul play?

The Better Sister is a taut, emotional ride where nothing is as it seems, and family ties are tested to the breaking point.