Major spoilers for The Whisper Man follow.

Netflix thriller The Whisper Man begins with one serial killer already safely behind bars – but by its final act, it becomes clear that his crimes have cast a far larger shadow than anybody realised.

25 years earlier, Detective Pete Willis (Robert De Niro) caught Francis "Frank" Carter (Michael Keaton), the murderer nicknamed the Whisper Man – after a figure in local folklore – because of the unnerving voice heard on recordings of his kidnapped victims.

In the present day, Pete's estranged son Tom Kennedy (Adam Scott) moves with his eight-year-old son Jake to his late wife's home town following her death.

Soon, children begin disappearing again, with the killer apparently following Carter's exact methods – including details of his crimes that were never released to the public.

So who is the new Whisper Man? What does Carter really want? And just who is the mysterious girl in the blue sweater who keeps appearing to Jake?

Here's everything you need to know about The Whisper Man's ending.

Who is the new Whisper Man?

The killer abducting boys in the present day is Frank Carter's son, Francis Carter Jr (Owen Teague).

For much of the film, the investigation suggests that Carter may have had an accomplice who was never caught.

When missing boy Neil Spencer is found dead, his fingernails have been trimmed before he was strangled – a detail of Carter's method that was never made public. Whoever killed Neil therefore had intimate knowledge of the original Whisper Man murders.

True-crime obsessive Norman Collins (Hamish Linklater) becomes an obvious suspect. Tom previously caught him trespassing in his basement, while police discover that he has been communicating indirectly with Carter through another prisoner. But Collins isn't abducting the children.

Tom and Pete discover the remains of Tony Smith – the fifth victim of the original Whisper Man, whose body Pete never recovered – hidden inside a concealed section of Tom's house. They also find the body of former resident Dominic Barnett.

Collins admits that Carter directed him towards Barnett, who allowed him access to Tony's remains. Collins subsequently killed Barnett after the ex-con mocked him, calling him a "tourist" and a "peeping tom".

Crucially, Collins also reveals what he gave Carter in return: he connected him with somebody on the outside. Before he can reveal more, Collins takes his own life.

Pete and Detective Amanda Beck (Michelle Monaghan) eventually realise who Carter would most want to contact – and who might be desperate to recreate his crimes. His own son.

Why is Francis Jr killing children?

The film draws a deliberate parallel between Tom and Francis Jr – two sons shaped by troubled relationships with their fathers.

Tom has been estranged from Pete for years, yet has grown up to become a crime novelist, his work clearly influenced by his father's career.

Carter even observes of Tom's novels: "He's trying to be you."

That remark helps Pete and Beck reach the truth. Looking back at footage of Carter's wife and young son following his arrest, they realise Francis Jr has similarly grown up mythologising his father.

But whereas Tom has fictionalised Pete's world, Francis Jr has gone much further.

He has become the new Whisper Man, recreating his father's murders in an attempt to earn the approval of a man who abused and traumatised him. Francis Jr was, in a sense, Carter's first victim.

Pete also finally understands why Carter covered the faces of the boys he murdered with T-shirts. Carter had himself been abused by his father and, Pete concludes, preyed on other boys instead of acting upon the violent impulses he felt towards his own son.

"You tried to stop yourself from doing what you really wanted to do to your boy… so you preyed on others," Pete tells him.

Why did Jake go with the Whisper Man?

Jake is particularly vulnerable when Francis Jr targets him.

He is grieving for his mother, struggling in a new home and increasingly isolated from Tom, whose own grief sometimes causes him to lose patience with his son.

Pete explains that Carter was skilled at identifying exactly these kinds of children: "Carter knew how to find the ones who wanted to go."

The Whisper Man rhyme makes the same point:

"If you're lonely, sad or blue, The Whisper Man will come for you."

Shortly before Jake disappears, he and Tom have a painful argument after Tom loses his temper over his son's supposed imaginary friends. Jake then initially goes with Francis Jr willingly.

Although his connection to Pete inevitably gives the kidnapping added significance, the film doesn't establish that Jake was chosen simply because he is Pete's grandson.

Rather, he is exactly the kind of lonely, unhappy child the Whisper Man knows how to exploit.

How do Pete, Tom and Beck find Jake?

Beck traces Francis Jr through Richard Sharmatz, the psychologist who had previously treated him.

At Sharmatz's home she encounters a man calling himself George Carrington, who claims to have been the psychologist's mentee.

Beck soon realises "George" is actually Francis Jr – and finds Sharmatz's mutilated body concealed inside a barrel.

Francis Jr catches Jake outside, however, and drives away with him before anonymously feeding the police a false lead.

Meanwhile, Pete returns to Carter for one final confrontation.

Having understood the truth about Carter's relationship with his son, Pete makes a desperate bargain: tell him where Jake is going and he will arrange for Francis Jr to be brought to Carter.

The answer leads Pete and Tom back to Tom's own house – the place where Tony Smith was murdered decades earlier. Francis Jr is taking Jake back to where his father's crimes began.

What happens to Pete?

At the house, Tom hears Jake crying but is attacked by Francis Jr before he can reach him.

Francis Jr then stabs Pete in the stomach with a screwdriver. Knowing the wound is fatal, Pete uses his remaining strength to help his grandson, telling Jake simply: "Run!"

Jake flees while Tom continues the fight. Francis Jr initially has the upper hand, but the dilapidated house itself ultimately brings him down.

Earlier scenes established that the property had serious structural problems, including leaking water and fragile flooring. During the final confrontation, Francis Jr crashes through a weakened section of the floor and falls, incapacitating him. He survives and is arrested.

Pete isn't so fortunate. The epilogue confirms that he dies from his injuries, completing his reconciliation with Tom through one final act of sacrifice.

Earlier, Tom had also finally understood a strange memory from his childhood. As a boy, he believed he had an imaginary friend called Mister Night, who would visit his room, read to him and kiss him goodnight.

Tom eventually realises Mister Night wasn't imaginary at all. It was Pete, secretly visiting his estranged son. His father's love was present even when Tom couldn't recognise it – and Pete's final act makes that love unmistakable.

What does Frank Carter really want?

Carter spends much of the film claiming that he wants to see his family again. But the ending reveals a far darker agenda.

Carter has been manipulating events from behind bars, using Collins and others to establish contact with Francis Jr – and by persuading Pete to promise him access to his son in exchange for Jake's location, he gets precisely what he wanted.

After Francis Jr is arrested, he is brought to his father's prison cell. Carter then recreates the method he used on his original victims: he covers Francis Jr's face with a shirt and strangles him to death.

It's the bleakest possible conclusion to Francis Jr's attempts to win his father's love. He has spent years trying to become Carter and earn his approval, only for that obsession to deliver him directly into his father's hands.

Recovering from her injuries, Beck receives a letter from him which reads: "Amanda – thank you for everything you and Pete have done for me – your friend, Frank."

With Pete gone, Carter apparently has a new detective to torment.

Who is the girl in the blue sweater?

The film's final mystery concerns Jake's supposed imaginary friend, the girl in the blue sweater.

Jake speaks to her throughout the story and says she is afraid of "the boy in the floor" – long before anybody discovers Tony Smith's remains hidden inside the house. He sees her again during the climax and afterwards tells Tom: "She saved me."

Initially, Tom's experience with Mister Night seems to offer a rational explanation. Tom believed Pete was an imaginary friend when he was young. Perhaps Jake is similarly turning something real into a childhood fantasy. But the film's final scene complicates matters.

Looking through old family photographs, Tom discovers an image of his late wife as a child, wearing a blue sweater. The mysterious girl Jake has been seeing therefore looks exactly like his mother when she was young.

So has Jake genuinely been seeing his mother's ghost? The film deliberately refuses to answer.

It's possible that the girl is a manifestation of Jake's grief – an imaginary version of the mother he misses, appearing when he most needs comfort.

But other details encourage a supernatural interpretation. How could Jake's imaginary friend apparently know that Tony Smith's body was concealed inside the house?

The final photograph therefore reveals who the girl represents without explaining exactly what she is. She might exist only in Jake's imagination – or his mother may genuinely have been watching over him.

Either way, Jake believes she saved him.

What does The Whisper Man's ending mean?

In the aftermath, Tom and Jake move into Pete's old house.

One small detail appears particularly significant: the crack previously visible in Pete's ceiling has been repaired. It can be read as a visual metaphor for the film's central theme – whether damage is passed from one generation to the next or finally repaired.

Frank Carter was abused by his father, went on to abuse and murder others and traumatised Francis Jr, who ultimately became his imitator. Their family never breaks the cycle.

Pete and Tom's relationship also suffered lasting damage, but their story ends differently. Tom learns that his father never stopped loving him, Pete gives his life to save Jake and Tom now has the opportunity to avoid repeating the mistakes of the previous generation with his own son.

The repaired crack suggests that this family, unlike the Carters, may finally be beginning to heal.

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