6 major differences between Netflix's 'The Perfect Couple' and the book it's based on — including a dramatically altered ending

• Warning: Spoilers ahead for Netflix's adaptation of Elin Hilderbrand's "The Perfect Couple."
• Elin Hilderbrand's book and the Netflix series have some key differences, including the ending.
• In the novel, Merritt's death is an accident. In the series, it's a calculated crime.

" The Perfect Couple ," Netflix's hit new murder-mystery series, follows Amelia Sacks (Eve Hewson) and her fiancé Benji Winbury (Billy Howle) ahead of their plush Nantucket wedding, which is called off after the dead body of the maid of honor, Merritt Monaco (Meghann Fahy), is found on the morning of the big day.

Benji's wealthy family immediately becomes fodder for tabloids and nosey neighbors as the police investigate every member of the wedding party, including Benji's famous crime writer mother, Greer Garrison Winbury (Nicole Kidman), and his father, Tag Winbury (Liev Schreiber).

The series is based on Elin Hilderbrand's 2018 novel of the same name.

While the adaptation has kept the story largely the same, it may still surprise book readers, as showrunner Jenna Lamia and director Susanne Bier have tweaked a number of key details, including the story's ending.

Here are some of the ways the show differs from the book.

1. Merritt's death is accidental in the book

Perhaps the most notable change that Lamia made when adapting the story for the screen involved Merritt's death.

In the book, the maid of honor's demise is very much accidental, even though it is Abby (Dakota Fanning) who is responsible.

After growing tired of her husband Thomas (Jack Reynor) carrying on his affair with a family friend, Abby crushes up a sleeping pill and mixes it into a drink meant for her rival, hoping it will mean she'll fall asleep before she can fool around with Thomas the night before the wedding.

However, Thomas's mistress ends up giving the beverage to Merritt, who drinks it before accidentally cutting her foot on some glass on the beach.

As she heads to the water to wash the blood off, she spots a piece of jewelry that Tag gave her at the bottom.

She dives in to retrieve it just as the sedative takes effect and ends up drowning.

In the show, things play out a little bit differently.

It's Amelia's terminally ill mother's euthanasia pills that Merritt unknowingly ingests, and Abby very much wants her dead.

Her motive is financial, not personal; Merritt is pregnant with Tag's baby, and if she were to give birth, it would reset the conditions of the Winbury trust fund — which stipulates that it won't be released until Tag's youngest child reaches the age of 18.

After crushing up one of the pills into a drink and giving it to Merritt, Abby lures her into the water under the pretense of taking a late-night swim together before holding her head under the water.

2. Justice is not served in the book

In the series, Abby is arrested for the murder.

In Hilderbrand's novel, however, Merritt's death is ruled an accidental drowning.

But that's not to say the murder remains undiscovered. Through her years of writing her own convoluted crime novels, Greer is able to piece the clues together and work out that Abby was responsible for Merritt's death.

However, to protect the family, the secret stays with her.

3. The bride-to-be is called Celeste, not Amelia

In the book, a woman named Celeste Otis is about to marry into one of the wealthiest families on Nantucket.

However, in the show, the character has been renamed as Amelia Sacks.

Explaining the reason behind changing the protagonist's name, Lamia told Netflix's Tudum that it was because Kidman previously played an "iconic" character named Celeste in the HBO series "Big Little Lies."

Although "the bride was named Celeste through many, many drafts of the script," the showrunner said the team didn't want to confuse audiences, so they changed it.

That's not the only name change from the book; Isabel Nallet, the French family friend of the Winburys, is British socialite Featherleigh Dale in Hilderbrand's novel, while Shooter Dival is Shooter Uxley.

The charming male detective known as "The Greek" in the book is also replaced by no-nonsense detective Nikki Henry (Donna Lynne Champlin) in the series.

4. Greer's scandalous past has been invented for the show

In the final episode of the show, Greer comes clean about her life before she was a fixture of the Nantucket social scene.

After being forced to admit to the police that Broderick Graham (Tommy Flanagan), the man who crashed her book party, is her estranged brother, she shares the full truth with her family.

Not only did she used to work as a high-profile escort, but Tag was one of her clients, who paid to have sex with her until they decided to pursue a relationship together.

Furthermore, there is no Broderick Graham in the novel at all.

The character and the plotline around Shooter wiring him money to help him pay off debtors have been created entirely for the show.

5. Will, the youngest brother, doesn't exist in the book

Will Winbury (Sam Nivola) is another new addition.

It appears that the teenager was brought in as a character after Lamia fleshed out Abby's motive.

Without the existence of Will, who is on the cusp of turning 18, Abby wouldn't have a reason to eliminate Merritt and her unborn baby.

Since Tag was the father of the child, its birth would delay Abby getting her hands on Thomas' share of the Winbury money.

6. The final scene of the series and the book are dramatically different

The very final pages of the book version of "The Perfect Couple" describe Merritt's accidental drowning, told from her perspective, and reveal to readers how she died since no one was actually with her in her final moments.

In the show, after Abby is arrested for the murder, things flash forward to six months later when Amelia has left the world of the Winburys and Nantucket behind her.

She is shown to be working at London Zoo when Greer surprises her with a visit.

Greer explains that she has written a book about Amelia and will not publish it unless she has Amelia's permission.

Speaking candidly about what happened in the summer, Greer admits that she used to hate Amelia but has come to admire her. Finally, Greer asks if Amelia would like to be friends with her.