Insomnia has come to a dramatic ending – with more twists and turns than a snake high on Emma’s leftover amphetamines – so you might need the final episode explained…

The six-part thriller kept us guessing until the very end, when the series came to a tense climax – and Emma’s new friend Caroline was exposed as the ‘villain’. But it wasn’t as simple as right and wrong, black and white.

In fact, the gripping series was a dark tale of childhood trauma, and what can happen if you don’t deal face your demons… Here’s everything you need to know about the ending of Insomnia on Channel 5, and the plot-line explained.

***Warning: stop reading TVGuide’s Insomnia ending explained unless you’ve watched all six episodes***

Insomnia ending explained: What happened in series finale?

As the Insomnia finale kicked off, Phoebe was recovering in hospital after being knocked over in a hit and run. Understandably, her near-death experience had bought the two sisters back together, and Phoebe began to talk more and more about their troubled past… Phoebe remembered at LOT more than her younger sister, whose memories had become confused.

Having spent years blaming her sister Phoebe for some horrid events, Emma realised her sister was not to blame. When Emma finally learnt the truth about her past – and Caroline’s involvement in it – she came to the sudden realisation that her family were in serious danger.

Of course, viewers saw Caroline arrive at Emma’s house and ingratiate herself with Robert and Chloe… Shockingly, she’d baked a cake laced with sedatives and persuaded them to eat it. But that wasn’t all… Caroline went on to murder Julian.

When Emma (Vicky McClure) eventually intervened to save her family, she came to a new understanding of her night-time activities and made peace with her ordeal.

Read on for a more detailed breakdown of what happened in the Insomnia series finale.

Who was Caroline Mitchell?

In Insomnia episode 5, viewers got quite the shock when Emma’s new friend Caroline Mitchell (Lyndsey Marshal) mowed down Phoebe in her car. Those of you paying attention would have started putting two and two together… She was the same age as Emma and Phoebe, and had previously seemed a little too good to be true.

Earlier in the series, Emma had accidentally knocked over Caroline on her bike (clearly not an accident), and the pair had subsequently become friendly. But, we soon learnt that Caroline had some skeletons in her closet too. Her dad had died in a car accident when she was young, leaving her with an infirm and suicidal mum – who later died after taking her own life. This seemed to be the last straw for Caroline, who subsequently became intent on seeking revenge.

In the series finale, we discovered that Caroline had also been at St Agnes children’s home at the same time as Emma and Phoebe. She was the one who had tried to drown Emma in the pond. In fact, Caroline’s parents had visited St Agnes to find a new sister for their daughter. They chose “perfect” Emma.

However, on the way home from their visit, they were involved in a horrendous car accident. The crash killed Caroline’s dad, and left her mum in a wheelchair. Caroline effectively became her mum’s carer overnight. Meanwhile, Emma went on to find good foster parents, a rather lovely husband, and had two kids in her huge suburban house.

But why blame Emma, who was as much as an innocent as Caroline? In the denouement, Caroline said: “I was a kid. I didn’t want a sister, I didn’t need a sister. No matter how much I pleaded, they would not listen to me.”

She added: “I wasn’t enough for them. They wanted you too. And it was because of you the crash happened.” In fact, Caroline’s dad crashed because she was kicking the back of his seat, and arguing with him.

What did Caroline do, and why?

In the series finale, Caroline was determined to have her revenge against Emma. She said: “Here am I all alone, exhausted. You have everything. […] Everything that’s wrong with me started with you.”

While Emma was with Phoebe in hospital, Caroline drugged Emma’s husband Robert, and his daughter Chloe. In a twisted attempt to live Emma’s life, she drank her wine, bathed in her toiletries, and even touched her husband (yes, THERE).

When Julian arrived in response to a message Chloe sent just before she passed out, Caroline dealt with him pretty swiftly… She broke the glass of the wine she’d been drinking and stabbed him in the neck with it.

Emma eventually returned home, and confronted Caroline who insisted none of this had been planned. That all her memories had returned after seeing Emma at the hospital several days previously.

She explained that she’d run Phoebe over because she’d seemed to recognise her. Caroline knew Phoebe would go to the police, and they’d arrest her, so there would be no one to look after Caroline’s mum. However, tragically, when Caroline returned, her mum had killed herself by smashing a glass and cutting her own wrists.

Who killed Emma’s mum Patricia?

Caroline killed Patricia. After visiting her own mum in hospital, Caroline saw Emma leave the hospital room where Patricia was convalescing. She knew that would make Emma the last person (except her, of course) to see her alive.

She killed Patricia out of pure malice, as well as hoping that Emma might be blamed.

During the emotional confrontation, Emma pretended to sympathise with Caroline and get her on side. But she saw through it, and attacked her. Caroline managed to stab Emma with a knife. However seeing the blood gave her flashbacks to when her parents had been involved in the car accident.

In yet another horrifying twist, we learnt through flashbacks that Caroline had actually killed her own father as he lay choking in his own blood after the crash. Unable to bear the sound of his laboured breathing, she smothered him with her cuddly toy – a knitted frog. He said “you’re better now” after he stopped breathing.

He could have survived the crash… So Caroline’s fate as her mum’s carer was entirely her own doing. Tragic but true.

Insomnia ending explained: How many people did Caroline kill?

By the end of the thrilling six-part series Insomnia, Caroline had quite the death tally. Not only did she murder her own father, she went on to kill Emma’s mum Patricia.

In the series finale, Caroline also murdered Julian when he got in the way of her plans to get revenge on Emma. Towards the end of the episode, Caroline had stabbed Emma, and had tried to smother Emma’s son to death with a pillow. Of course, this was an exact re-enactment of what Emma’s mum Patricia had done to Phoebe during her psychotic breakdown. That time, Emma had walked in on her mum and interrupted them. When Patricia realised what she was doing, she was horrified and backed away from Phoebe’s bed.

Of course, Emma was able to stop another murder here too. Just in the nick of time, Emma smacked Caroline over the head with a cricket bat. Who said cricket was a gentleman’s sport?

Despite being stabbed and losing lots of blood, Emma survived the ordeal. As did her whole family, including sister Phoebe, with whom she enjoyed a new closeness. The humungous house was up for sale, and Emma had a new job at a new firm.

What did the mum have? And was it hereditary?

Emma and Phoebe’s mum Patricia suffered a psychotic breakdown on her 40th birthday. She then lived her days in a secure unit called Helmswood, while her two daughters were put into foster care. But what was her diagnosis? The girls had never been told.

In episode 5 of the thriller, Emma discovered Patricia believed there had been a history of mental illness in the family – which pointed at it being genetic. However, the doctor told Emma that this could also have been a “facet of her mum’s paranoia”. Before her breakdown, Patricia complained of insomnia, and was treated for burns on her fingers – an accident while sleep walking… And it sounded rather familiar to Emma, who was suffering these exact symptoms herself.

Her actual diagnosis though? The doctors believed she may have had paranoid schizophrenia. However, Patricia also had selective mutism, which is something usually seen in children. Suffice to say that Emma did not have ‘bad blood’. It was revealed to be rather more ‘mystical’ as the final episode went on…

Insomnia ending explained: What did the numbers mean?

Both Emma and her mum suffered a type of mania, where they recited the same sequence of numbers over and over. But what did the numbers mean?

During her stay in hospital, Emma had a lot of time to think about the numbers (which miraculously seemed to have disappeared by this point, as had all of Emma’s bizarre sleepwalking behaviours).

Emma explained that when she first woke up, it was 1.01am. Just before she passed out, it was 2.33am. During Caroline’s hostile takeover of Emma’s house, she rattled the doors closed, and lit the candles – just like Emma and her mum before her. The time stamp on the footage as she did each thing was 1.25am, 1.55am, and 2.10am. The time all of them lifted a pillow over someone’s head? 2.33am. They were all displaying the same behaviours at the same time.

Emma told her sister: “I don’t think her numbers were random. I think they were times.”

So what was it all about? The plot twist at the end was that Patricia was having premonitions about the future. She was acting out the premonitions, or warnings, but she didn’t understand them, and couldn’t control them. Of course this knowledge finally allowed Emma to forgive her mum.

Patricia was essentially “driven mad” reenacting these premonitions from the future. Of course, if Patricia had not been admitted to an institution, there would have been no care home, no meeting Caroline at St Agnes, and not family fall out. So Patricia actually caused the problems. Phoebe likened it to an ouroboros, an ancient symbol commonly depicted as a serpent or dragon eating its own tail, forming a circle.

What is an ouroboros?

An ouroboros represents the cyclical nature of life, death, and rebirth. Or as Phoebe said it: “A constant endless loop.” While Emma believed she’d broken the cycle, a quick visit upstairs proved she hadn’t.

Unbeknownst to Emma and Robert, their young son Will was writing those very numbers across a bedroom wall. Just like Emma and her mum Patricia had done in the past.  You definitely had to suspend disbelief for this thriller, but we bet you didn’t guess the ending!

One fan wasn’t impressed though, typing: “Rubbish ending to #Insomnia. Some kind of mystical connection woo woo bollocks. Why do they always do this with thrillers. Learn some science, please!”

Another said: “Insomnia’s ending is really bad. It doesn’t tie the storyline together well and feels quite a rushed ending. Shame because the rest of the show was really good.”

We hope our Insomnia ending explained help viewers find some closure!

Will there be a series 2 of Insomnia?

Neither Paramount+, who originally aired the thriller, nor Channel 5 have confirmed a series 2 of Insomnia. The six-parter was based on a book, of which there’s no sequel.

Although the series left something of a loose end – Will exhibiting Emma’s bizarre behaviour – it’s unlikely to come back.

Our advice? Don’t hold your breath!

Read more: 10 of the best ‘hidden gem’ TV dramas you can stream for free right now to get you through the summer of sport

Insomnia is currently available to watch on Paramount+ and Channel5.com.