At the heart of Nine's controversial reality series The Briefcase is a lie. In one of the most outrageous examples of the old bait-and-switch you will ever see, couples were signed up believing they were making one show, only to find themselves appearing on another.

"We told people we were doing a show called Making Ends Meet, in which we were going to come and speak to them about their financial situation and provide some financial advice," explains Andrew Backwell, head of programming and production at Nine. Instead, they found themselves on a show in which all their financial worries would be solved thanks to a simple contrivance.

A briefcase full of money – $100,000 arranged in 10 fat stacks of 20s – lands on the doorstep. Inside is a note: the money is theirs to keep, but there's a catch. They will learn about another family that is also doing it tough, and will have to decide who deserves the money more. Should they keep all of it, some of it or give it all away?

Goodness, who left this briefcase here and what on earth is inside it?

Unbeknownst to each family, the other has also been given a briefcase full of cash, and set exactly the same moral dilemma. Although it plays out as a surprisingly moving exploration of the capacity for empathy and compassion, you can never escape the fact that there's a chance one family may end up with 200 grand while the other leaves empty-handed.

Backwell says he bought the format over the phone from its creator Dave Broome (who also dreamt up The Biggest Loser) before the US version had even gone to air; you have to wonder if he might have been a little less eager had he seen it. The US show – which in one instance pitted a couple of white extremists against an African-American family – was roundly condemned for exploiting prejudice (not to mention the very poor) for entertainment.

Backwell insists Nine's version is a far gentler beast. "In America it was more a freak show," he says. "We've tried to go with average families that have fallen on hard times. Not by being slack or lazy or not giving a shit, but through no fault of their own. You're going to look at them and feel some compassion."

It's certainly hard not to empathise with the couples in the first episode. Farmers Jim and Jenny Carter have been going backwards since fire destroyed their farmhouse in the Grampians and destroyed much of their livestock (the house was insured, the farm wasn't). The McCrackens, from Kilmore, aren't exactly poor, but they've been living on welfare since Rod quit his job as a teacher to look after Mandy, who lost all four limbs as a result of a strep infection (they have three school-age daughters).

Rod and Mandy McCracken at home in Kilmore.

The McCrackens say they were open to the idea of sharing their struggles on the show they thought they'd signed up for, and utterly unperturbed when they discovered the truth. "We're more than happy to talk about what we've been through so other people can see what life can throw at you," Mandy says. "Anybody watching this show could be in the same situation with a flip of the coin."

Rod likens the sleight-of-hand to the sort of moral puzzler he used to set his year 12 philosophy students.

"Deceit was part of my arsenal," he says. "What's wrong with deceit if there's good to come from it? If you were to cast this show and tell people from the outset this is what we're doing, wouldn't you necessarily get people who are grasping at celebrity?"

In making people think about the balance between self-interest and generosity, Rod believes the show is "holding up a mirror to middle-class Australia and asking how does it feel". "The questions of what are we doing for refuges and the homeless become an extension of this," he says. "We're a metaphor, and I think that has great power."

For Honey Richmond, who appears with partner Kevin Shanhun in the second episode, filming the show was at times traumatic (she suffers from a stress-related condition and says she was at times quite sick) but ultimately "an amazing and uplifting experience".

The couple – who have four children together – have been living in rented accommodation for years since Kevin, a builder, sold the family home to ensure his sub-contractors were paid after a client failed to pay him.

Inside each briefcase is the above note.

They often talked about what it would take to turn their situation around, and the figure they always came back to was $100,000. "That to us was a huge amount of money, that could change our life," Honey says.

When the cash turned up, Kevin was initially suspicious. "There was a lot of joy, but I thought there's got to be a catch."

Of course, there was.

The crew separated the couple for the first night after the big reveal. Kevin took his kids to the cinema, "which was a clever plan because we couldn't speak". Honey says she "cried the whole time".

But all that emotional intensity wasn't just about deciding what to do with the money.

"There were things I'd locked away, that had been bottled up for years, about selling the house," Kevin says. "It finally came out."

"He felt he'd let the family down," Honey explains. "We'd never really talked about our feelings about it, we just talked about what we needed to do to survive. With this, I was able to say to him, 'No, Kevin, you didn't let us down'."

The experience – and, let's face it, the cash that came their way – has refocused their relationship. "We're getting married finally, after 23 years," Honey says. "We're like teenagers again."

Troy Hockley – who was, with wife Mem, on the other side of the conundrum facing Honey and Kevin – says the experience was daunting. "I saw the briefcase and I felt like I was one little person in a massive coliseum. This is a full-on rollercoaster – but it was fantastic. I like rollercoasters."

But did you feel any sense of betrayal when you discovered the true nature of the show?

"It was a bit like 'how dare you throw me a surprise party'," he says. "It's a bit of a shock, but you can't really get upset when someone gives you a large sum of money."

In fact, none of the people I spoke to has anything bad to say about the experience of making the show, though the McCrackens have been disappointed with the response in the media, where the show has been characterised as "poverty porn" that mercilessly exploits its participants for our entertainment.

"It's hard for us to watch the conversation going on around us when people [in the media] have never even asked our opinion," Mandy says.

"To me, it's the middle-class sense of privilege that feels the need to defend the 'poor' person, without a phone call to us," Rod says.

As far as he's concerned, "the 100 grand was just the vehicle for the discussion, not the carrot put in front of the 'poor McCrackens'.

"The only discomfort is in not having a voice in a conversation that involves you."

The Briefcase is on Nine, 7.30pm Monday

Karl Quinn is on Facebook and on twitter @karlkwin