The Au Pair proves yet again that Channel 5 is the master of fast-paced, edge-of-seat thrillers, with another ending that was FAR from predictable - here's episode four explained, and news on a possible series 2.

The four-part series felt like watching a car crash happening in slow motion. Like a good page-turner, The Au Pair had twists and turns aplenty - some preposterous but all engaging.

And the villain? Well, there was more than the average amount! So here's a recap of Channel 5's The Au Pair in our ending explained, and what we know about a possible series 2.

***Warning: spoilers from The Au Pair on Channel 5 ahead***

The Au Pair ending explained - who was Sandrine?

The Au Pair introduced Zoe Dalton (Sally Bretton), a woman who seemed to have it all - including a successful husband, two stepchildren, a thriving tailoring business, and a gorgeous countryside home in a picturesque English town. And we mean STUNNING home.

However, when the family decided to hire an au pair to relieve the pressure, everything started to go seriously pear-shaped.

After Zoe reluctantly agreed to hire an au pair, Sandrine seemed the perfect fit. However, viewers were soon enlightened as to her real motives. Sandrine was actually a revenge-seeking missile, intent on wrecking havoc on the mother she felt had abandoned her at birth.

Sandrine ticked every villainous box - she tried to ruin Zoe and Chris' life, gaslit Zoe at every turn, and even drugged Zoe's diabetic father. We believed the au pair was the dangerous one, but Zoe was surrounded by people who had done, and would continue to do unspeakable things. We subsequently discovered that Sandrine was also a victim, and the real villains were also living under the same roof as Zoe...

Why was Sandrine taken away from Zoe at birth?

Sandrine was actually named Stephanie Lacroix. She was born May 01 2002, the day Zoe gave birth to a baby girl.

In a horrifying twist, she was taken away from her mum Zoe without her consent. After birth, she was told that her newborn baby girl had been taken away because of complications. Zoe was later informed that her baby had died of asphyxia. The baby was buried, and Zoe was left to her grief. But her baby was alive, and had been illegally adopted to a couple in France.

Zoe's father George (David Suchet) had organised the illegal adoption. We learnt that Zoe had fallen pregnant at the age of 15 while drunk at a party, and her dad thought he was doing the right thing by taking her baby away.

He believed he was helping his daughter and giving his granddaughter a better start in life. But, unbeknownst to him, the baby was not given to a good couple. Instead, she was sold to the highest bidder. Subsequently, her adoptive parents treated her very badly. She was beaten, starved and humiliated.

Rebelling against her unfair life, Stephanie/Sandrine then began shoplifting, committing common assault, fraud, identity theft, and even arson. When a mysterious woman who had been involved in her adoption called her to inform her of her real mum's identity, Stephanie flew to the UK to find out the truth.

The Au Pair on Channel 5 recap

In the Channel 5 thriller, Zoe's dad was the mastermind behind Zoe's baby being taken away from her. A doctor, he was able to use his contacts. He then did the unthinkable - lied to his daughter Zoe about the fate of her baby. Zoe's mum, a midwife, was also complicit in the lie.

And, in yet another twist, we learnt that Zoe's husband Chris was also involved. Even worse, he was in it up to his neck!

Zoe's father George had worked with Chris at the time of Zoe's baby being born. He had asked Chris, a junior doctor who looked up to him, to help get the baby to France for adoption.

However, once there, Chris was corrupted and knew about the baby being sold to the highest bidder. He subsequently got involved in the illegal blackmarket adoptions in a bid to make money. Which probably explained the magnificent house.

Chris (Vera star Kenny Doughty) found young, pregnant women who could be exploited, and convinced them to give up their baby. He would then sell the baby to the highest bidder over in France.

What happened in the episode four finale?

At the end of The Au Pair on Channel 5, Chris was arrested. Not only had he taken part in the illegal blackmarket adoptions, he had abducted Sandrine with intent to kill her, and had also tried to kill George.

Meanwhile, Zoe's dad George was prepared to take full responsibility for his part in Stephanie/Sandrine's illegal adoption. In fact, he eventually made peace with both his daughter and his granddaughter.

Zoe, pregnant with Chris' child, enjoyed the family scene she'd been dreaming of for years, alongside her long-lost daughter Sandrine, and her step-children.

Like many Channel 5 thrillers before it, you had to suspend disbelief quite a lot here. The series is preposterous in places and very silly, but it made us shout at the telly in a good way. It's pure escapism, and it was well worth watching just to see David Suchet come out of semi-retirement!

Is there a series 2 of The Au Pair?

Channel 5 has not confirmed a series 2 of The Au Pair and it's looking unlikely. Much like previous C5 thrillers including The Wives, and The Castaways, these easily-digestible thrillers are short and sweet, and come to an end after four episodes.

There'd be little need for a series 2, as everything was neatly tied up in series 1. However, watch this space for more info, as we'll let you know if anything changes.

The Au Pair is currently available to watch on My5.