On Monday, April 8, 2002, Emma Connell walked into a Melbourne police station to report that her mother Margaret and stepfather Paul were missing.

The previous night, Emma had called the couple's children and friends after being unable to make contact with them for three days.

The couple were usually very social, and her mother never went out for more than a couple of days without talking to Emma or returning her messages.

But in the last three days, they had missed a number of lunch and breakfast reservations, and Emma was concerned that they hadn't answered the phone or returned her calls.

Emma's four siblings all claimed to not have seen the couple for weeks or to have any knowledge of their whereabouts.

After completing the Missing Persons report, Emma spoke to her siblings and arranged a family meeting to discuss their disappearance.

To their surprise, her brother Matthew confessed he had in fact hosted the couple for dinner the previous Thursday, something he had failed to mention the previous day when they spoke.

This revelation made Matthew the last person known to have seen his mother and stepfather, so what had become of the couple after dinner and how was Matthew involved?

This is Monsters.

Matthew Robert Wales was born in 1968 to parents Margaret and Brian Wales in Canberwell, Melbourne.

He was the youngest of five children, and while Margaret was a loving and caring mother, he had little to do with his father.

Brian was a pilot and spent long hours of time away from home, leaving Margaret responsible for raising their five children and taking care of the family home.

From the outside, she appeared to be living the perfect life with a generous home in a wealthy suburb and holiday homes at seaside areas and ski resorts, but Margaret was far from happy.

She was lonely and unsatisfied in her marriage, and with each new trip her husband took, she felt more distant from him.

In those days, he was unbecoming of a woman to leave her husband, especially when he was a respected pilot whose career provided a comfortable home life for his family, so Margaret took a different approach to secure the affection and comfort she desired.

During a family holiday, not long after Matthew was born, Brian met and became friends with Paul King.

Paul was a successful businessman who was vacationing at the same resort as the family.

The pair had a lot in common and thus began a friendship which expanded to include Margaret and endured for many decades to come.

It was during one of Brian's long stints away for work that Paul visited Margaret at home and their friendship transformed into something altogether more sexual.

Paul reignited a spark in Margaret that she didn't know she had been missing.

It was no fling and over the coming years they continued their affair, even going so far as to have Paul join the family on overseas holidays.

Unbeknownst to Brian, it was all a ploy for Margaret and Paul to be able to continue their affair without interruption.

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