It is the Netflix show starring Michelle Keegan as grieving mother Maya Stern that has delighted and frustrated viewers in equal measures over its explosive eight-episode run.
Fool Me Once has gripped fans of the streaming channel with its labyrinthine plot, stand-out acting as well as its numerous twists and turns.
But as many reach the end of the final dramatic episode, questions have been raised about some elements of the series.
Chief among those are a series of apparent plot holes and unexplained storylines leaving some as confused as Maya’s beleagured brother-in-law Eddie.
Here MailOnline identifies seven of the more baffling sections. Warning, spoilers are ahead so do not read on if you have not yet finished the show.
Suspicious Shane’s track attack and stalking
On top of a number of secret lingering looks at Maya, that hint at unrequited love or even obsession, Shane carries out a number of bizarre activities
Shane at one point places a tracker on her car underneath a wheel arch, although never appears to use it
In the series Shane Tessier – played by Emmett J. Scanlan – is at the centre of viewers’ suspicions for most of the show.
The character is a Military Police officer and is a key part of how Maya figures out the truth about her sister and dead husband Joe.
But he is seen behaving extremely strangely for much of the programme, for reasons never completely explained.
On top of a number of secret lingering looks at Maya, that hint at unrequited love or even obsession, he carries out a number of bizarre activities.
During one part of the series he appears to have broken into her house, a fact only revealed when she rings him to lie she is at home herself.
Elsewhere at least two scenes show him skulking around outside the property spying on her.
And perhaps most ludicrously he at one point places a tracker on her car underneath a wheel arch, although never appears to use it.
Former Military Police officer Mike Neville told MailOnline: The copious use of the trackers would just not happen.
‘Equipment like that has to be organised and authorised properly for investigations.
‘You can’t just get them out of stores and used if and when. You can’t use them for things like they are on the show.’
Why was DS Kierce taking the pills anyway?
Detective Sergeant Sami Kierce is shown throughout the show necking prescription pills
At one point his troubled mental state takes him to a bridge where he considers suicide
Actor Adeel Akhtar gives an accomplished performance as Detective Sergeant Sami Kierce, giving an emotional turn as a cop on the edge.
Central to the series’ whole plot is the discovery that the villainous Burkett family has been covering up side effects of drugs its pharmaceutical company produces.
This in turn leads to a dramatic reveal about DS Kierce, who has been suffering seizures, passing out and hallucinating his dead fiancee.
He is shown throughout the show necking prescription pills from a bottle and has a brain scan revealing a mystery illness is causing major damage.
At one point he considers taking his own life on a bridge as he fears he will no longer be able to function properly.
But viewers and he discover towards the end of the show the Burkett brand name on the label, which leads to the realisation that it is the drugs making him more sick.
In the memorable scene he looks at the bright white sticker on the bottle and sees it in block letters jumping out.
But it is never properly explained why DS Kierce had started taking the pills and what they were supposed to be treating.
It is also something of a stretch to imagine a detective – whose job is investigation and attention to detail – would miss the name on the label.
The brand is, after all, the same as the surname of the murder victim whose case he is looking into.
The interested helicopter pupil left in a field
The helicopter pupil was sat in the cockpit in the air with Maya and seemed to be listening in and hugely interested
The character is literally abandoned – by Maya – after she lands the aircraft in a field after chase
During episode three of the series Maya is in hot pursuit of a mysterious red car that has been trailing her.
In keeping with the apparent abundance of these types of gadgets, she had placed – you guessed it – a tracker on the vehicle.
But she loses the car in traffic on a dual carriageway and goes to work, where she instructs people on how to fly helicopters.
It is at this point Shane gives her a call to tell her the vehicle is on the move and she realises that it is near her location.
The viewer’s gaze is drawn to her pupil who is sat in the cockpit in the air with her and who seems to be listening in and hugely interested.
His expressions during the helicopter pursuit suggest he is someone involved in the case, but this is never developed.
In fact he is literally abandoned – by Maya – as the character lands the aircraft in a field.
As she leaps out to begin her pursuit on foot he is heard bemoaning the fact he has a dentist appointment to go to.
She promises to return to him but is not seen going back, the next time she appears he is nowhere to be seen.
Presumably he is still in the helicopter he is not qualified to fly sat in a random field.
Does Lily have sixth sense and see the dead?
As Maya tries to get her into the car, Lily can be heard saying ‘Dadda’ next to a large bush
At another point in the drama it is said that Lily has been drawing pictures of angels herself
Much is made of whether Maya’s husband Joe, who is played by Richard Armitage, is really dead.
From the questions over the nannycam footage, to the fact his official death paperwork is missing, the viewer is constantly kept guessing.
One of the main reasons for this is the behaviour of Maya and Joe’s little daughter Lily.
Early in the series she is said to have been drawing angels and seems to barely notice her father is no longer around.
But the strangest moment comes towards the end of the set of episodes as the plot begins to be tied up properly.
After scenes suggesting Joe could be alive and outside watching the property she is taken to the car later with Maya.
But the little girl insists on waiting next to a large bush next to the house.
As Maya tries to get her into the car, Lily can be heard saying ‘Dadda’.
It is heavily hinted Joe could be hiding in the bush but this is never explored again or even explained. Perhaps the bush is called Dadda.
Maya’s secret gun is missed by the police
Maya’s secret gun is missed by the police in a baffling oversight that does not ring true to form
The fact Maya’s husband has been shot dead does not lead to the secret gun being found
Despite the strict laws on firearms and how they are kept, Maya has a veritable arsenal in her home.
The rifles and a decommissioned handgun on display are explained away by her and officially registered, as she tells DS Kierce early on.
But a key plot twist centres on a secret compartment in her gun cabinet, which contains a working handgun.
In one of the most baffling oversights, DS Kierce only misses it because a bag is placed over the top of it.
This is despite him taking a great interest in the other guns and the other decommissioned firearm.
Given the fact her husband had been shot to death, it is inconceivable more attention would not be given to searching the cabinet.
On top of this, in real life the structure would have been carefully checked by police checking how they were stored.
Mr Neville, who is also a former Scotland Yard detective, told MailOnline it would be impossible to be missed.
He added: ‘This is more nonsense. Police check gun cabinets incredibly thoroughly to the point of sometimes being quite awkward and inconvenient.’
Theo Mora’s murder would have been found
Theo Mora is tied to a chair before a funnel is put down his throat to force him to down vodka
The fact there were rope marks on his arms would have triggered a police investigation in real life and the murder most likely uncovered
The disturbing murder of schoolboy Theo Mora is another key plot point in the series.
As a child Joe, his brother Andrew, and their friends took him to abandoned ruins in a sick prank.
Wearing masks, they tie him to a chair before putting a funnel down his throat and forcing him to down vodka, killing him.
His body is abandoned elsewhere and is found in the grounds of the school after the other boys swear to secrecy.
Joe later murders Andrew as the latter says he will go to the police to confess.
In reality there is little doubt the murder would have been discovered anyway.
The combination of circumstances would mean an inquest and police probe would have been launched.
Mr Neville adds: ‘The boy who died, there would have been an autopsy and a toxicology report that would have led to an investigation.
‘Of course any suggestion of rope marks on him would also lead to this. It would have been investigated properly.’
The magically appearing Burkett nannycam
The Burketts’ encounter was livestreamed on a nannycam pictureframe, but when was it placed in the room?
Surely Maya – who carefully plotted murder cover up – could have avoided dying herself?
The climax of the series features Maya taking a final revenge on the Burkett family.
She tricks them into confessing they knew about the drugs they make being dangerous and covering up the results.
Then she effectively goads Joe’s brother Neil into shooting her dead.
The Burketts have no idea but the whole encounter has been livestreamed on a nannycam pictureframe placed in the room.
But exactly how it was put into the precise location there is never explained.
And given the rings she has run round everyone covering up Joe’s death, Maya’s last act appears unconvincing.
For someone who has set up exposing the family to the world, it appears unlikely the only solution she arrived at meant she had to die.
There is also her sudden lack of regard for her daughter Lily, now an orphan.
In the final scene of the series – set years later – Lily seems unbothered by her family history as she gives birth to a daughter.
She is so forgiving to her mother, she even names the child after her.