Who killed [SPOILER] in The Perfect Couple, and why?

A star-studded limited series was just added to Netflix's library today, and I have a feeling it's going to become very popular. The Perfect Couple, based on the 2018 novel of the same name by Elin Hilderbrand, is a murder mystery set in wealthy Nantucket. Starring Nicole Kidman, Liev Schreiber, Meghann Fahy, and other familiar faces, the six-episode series takes us through a whodunit case as authorities and partygoers try to piece together what happened the night before a wedding. At the very end of the show, we do get our answers, but you might be scratching your head at the motive(s).

WARNING: Major spoilers for The Perfect Couple are below.

The Perfect Couple revolves around a murder that happens the night of a wedding welcome party. The matriarch of the rich and powerful Winbury family, Greer (Kidman), is getting ready to give away her one of three sons, Benji (Billy Howle), in marriage, while her husband Tag (Schreiber) is up to some sketchy business. The bride, Amelia (Eve Hewson), doesn't fit in with the family, not having come from money, and blending the two families isn't exactly organic.

As we learn at the end of the show's premiere, the body Amelia finds washed up in the ocean is her best friend and maid of honor Merritt (Fahy). So what happened to her, and why would someone want her dead? Throughout the six episodes, we're presented with plenty of red herrings, but we do get our explanation in the end. And the killer is probably not who you were thinking.

The killer in The Perfect Couple is... Abby!?

By the finale of The Perfect Couple, it's revealed that Benji's pregnant sister-in-law Abby (Dakota Fanning) is the killer! There's no way anyone saw that one coming. Throughout the series, Thomas' (Jack Reynor) wife keeps to herself, though it's pretty obvious she doesn't mind dabbling in some drama. A pill fiend, Tom ends up stealing barbiturates from Amelia's mother, who is sick with cancer. But it's Abby who ends up using one of the pills, crushing it up the night of the welcome party and putting it in a drink she offers Merritt on the beach. Once Merritt gets woozy from the pill, Abby pushes her into the ocean and drowns her.

The authorities on the case, Chief of Police Dan Carter (Michael Beach) and Detective Nikki Henry (Donna Lynne Champlin), figure out who killed Merritt and they arrest Abby. Justice for Merritt is served and Abby will presumably spend a lot of time behind bars, but let's back up for a second. Why would Abby even want to kill Merritt? That's probably the question on your mind when you finish The Perfect Couple.

Well, there are probably a few reasons Abby would want Merritt dead. But the most obvious one has to do with money. It's revealed that all of Tag's family money is placed in trust funds, which is why Greer continually churns out new books. She's the breadwinner here. Tom is thousands of dollars in debt with family friend Isabel (Isabelle Adjani), and after his father denies him a loan, he counts on the trust fund money to help him out.

But there's one complication. Though the family believed the siblings would get the money once the youngest, Will (Sam Nivola), turned 18, he might not actually be Tag's youngest child after all. It's revealed Tag impregnated Merritt, meaning money would be allocated for their child if she had it — and Tom would have to wait an additional 18 years for his money.

It's pretty evident that Abby enjoys her luxurious lifestyle and wouldn't do well without money, especially with a child of her own on the way. This is the biggest reason she would want Merritt dead. Though Tom considers killing Merritt, even pointing a gun in her direction, he can't bring herself to do it. So Abby takes it upon herself to carry out the deed.

Another potential reason Abby could have hatred for Merritt is the infidelity aspect. Abby discovers that Tom is having an affair with Isabel, and she might look at Merritt with bitterness because she is sleeping with Tag. Though this probably isn't enough reason for her to kill Merritt, it does add an extra layer to her motivation.

Now that Abby's been arrested for Merritt's murder, however, she has bigger things to worry about than money. Yikes. The Perfect Couple might not have the most satisfying of reveals, but with only six episodes, I'm sure people will enjoy the show as a quick weekend binge.

All six episodes of The Perfect Couple are streaming on Netflix.