The Block returns for 2012 as eight new couples meet their host Scott Cam in Melbourne to compete in a fierce elimination challenge that will see the final four move into this year's Block.

The competition heats up in the Red Elimination House as The Block hosts a state of origin clash when Brad & Lara from NSW take on a father and daughter team Larry & Jessie from QLD.

It's the battle of the newlyweds in the third of 4 elimination challenges, Sophie & Dale, married just 5 months will take on Brendan & Michelle, married for one year.

In tonight's episode, the last of the Red House eliminations, two brothers Andrew & Mike from NSW will take on the show's first ever mother and son team, Rana & Brett from VIC for the last remaining house on The Block.

Four couples have made it through the elimination, and now the fun really begins. Host Scott Cam welcomes them to Luna Park in Melbourne for their next big challenge to find out who gets first choice of the houses at the block.

Go behind the scenes with judges Neale Whitaker, John McGrath and newcomer Shaynna Blaze as they review their judging of this week's eliminations.

Host Scott Cam introduces the couples to their new homes, four dilapidated, gold-rush-era houses in South Melbourne with dirt floors and just a few walls. All the teams realise that the next 10 weeks of their lives are going to be tougher than they could have ever expected.

Challenge master Shelley Craft puts the couples through their next big challenge.

The couples are tired, the conditions are primitive, and they have to get their first room ready for the judges, who will arrive again in just a few days.

The couples are called into Scotty's workshop for the first time. Their challenge is to design and build a piece of furniture for their homes, but Scotty has a big twist as one couple will win a bonus point to put towards their room total.

Scott Cam and Shelley Craft review progress as the couples struggle to complete their first room. All are feeling the pressure.

Go behind the scenes with judges Neale Whitaker, John McGrath and Shaynna Blaze as they review the contestants progress on room one.

The couples race to deliver their first rooms for the judges. The competition is fierce for the $5000 weekly room prize, which will be decided by Neale Whitaker, John McGrath and new judge Shaynna Blaze.

There's gold fever at the block as challenge master Shelley Craft takes the teams out of the city to strike it rich in the Victorian goldfields. But the winning teams are in for a big shock as Scott Cam announces one very big twist.

The teams risk it all in the goldfields in an effort to try to double their winnings - or lose the lot. Then it's back to the block to continue two-room week, and all of the couples are really feeling the pressure to deliver their hardest task yet.

Host Scott Cam springs another challenge, and this time there's an all-important bonus point up for grabs. But back at the block, there's trouble with the tradies, and one team is about to pull the plug on their bathroom renovation.

All four couples are desperately trying to keep their renovations on track for this week's room delivery as Scott Cam and Shelley Craft drop in to review progress of their master bedrooms and ensuites.

Take an in-depth look back at the first week's room deliveries as the judges explain their decisions and the couples review each other's rooms during the open for inspection.

With $10,000 on the line, the four couples rush to complete their room delivery of the main bedrooms and their ensuites. It's the end of a hellish two-room week, and at least one team will not finish on time for the judges.

After delivering two whole rooms for the judges, the couples face an even tougher task: challenge master Shelley Craft gives them two rooms in one day! Guest judge Darren Palmer will award one team an extra $5000.

Site Foreman Keith has some bad news for one team as they try to redesign their powder room under the stairs. With an upstairs guest room to deliver as well, everyone is feeling the pressure.

The teams are called into Scotty's workshop for a crash course in upholstery, which turns out to be a very tough challenge for two teams who have never used a sewing machine before.

The race is on to finish another two rooms but a sudden game of paint ball puts a halt on renovations. Also, the boys decide to test their pain barriers by engaging in some friendly waxing.

Judges Neale Whitaker, Shaynna Blaze and John McGrath review the master bedrooms and ensuites, and the couples look over each other's rooms for the first time.

The teams are racing to complete their second two-room week and deliver their guest bedrooms and powder rooms. It's the closest judging so far, and this time the all-important bonus points will come into play.

Challenge Master Shelley Craft goes green with a pedal-powered challenge: Each couple must generate their own electricity to make a DIY windmill. But what starts out eco-friendly quickly goes downhill.

It's bathroom week and everyone is having issues with their renovations. Dan and Dani have spent $5000 on a bath but then discover it won't fit. One team breaks the noise restriction rules, and the others are not happy about it.

Host Scott Cam has set the couples a mind-bending challenge when he presents them with the world's hardest flat-pack. There are bonus points on the line if they can complete it - and a hidden message from the judges.

The issue of noise restrictions is a hot topic, and now Dan is upset at Dale about breaking the rules. Scott Cam and Shelley Craft review progress as the couples struggle to complete their bathrooms.

The Block's judges - Neale Whitaker, Shaynna Blaze and John McGrath - review their decision about the teams' guest rooms and powder rooms, and the couples give their views of their neighbours' efforts.

Challenge master Shelley Craft takes the teams to Daylesford in country Victoria, where they will have just five hours to style a room for Belle Magazine and be judged by editor Neale Whitaker.

In their race to complete a bedroom and their hallways, some teams try to cut corners, which puts them in the firing line with site foreman Keith. Host Scott Cam tries to teach Dan how to say no to Dani, with hilarious results.

Host Scott Cam brings in some very tough clients and judges as the teams are set the task of building the world's best cubbyhouse in the workshop challenge.

The teams have finally reached the halfway mark in their renovations and reflect on the last 50 days living at the block. Scott and Shelley stop by to see how the teams are progressing with their hallways and guest bedrooms.

The judges - Neale Whitaker, Shaynna Blaze and John McGrath - review their decision about the teams' main bathrooms and laundries, and the couples give their views of their neighbours' efforts.

The teams are working all-nighters again in their efforts to complete their guest rooms and hallways. Judges award one team the highest scores of the series so far to win the weekly $5000 prize.

The teams are blessed by local priest Father Bob before setting out on a challenge set by Shelley Craft to raise money for his foundation to feed the homeless.

The teams are trying to protect their city views during the renovations of their rooftop terraces, and everyone is hoping for divine intervention as they face the crowds at the charity auction to raise money for Father Bob.

Host Scott Cam presents the couples with the toughest challenge they have faced: The winner will be the team who can complete the most renovation tasks in one 24-hour period.

The teams are juggling budget problems with the needs of getting trades and materials in order to complete this week's rooms. With just a day to go every team is feeling the stress of another very tough week on the tools.

The Block's judges - Neale Whitaker, Shaynna Blaze and John McGrath - review their decision about the teams' main bathrooms and laundry areas.

With just four hours to go until room reveal, all four teams are rushing to complete their rooftop terraces in time for the judges. As budgets are getting tighter, everyone is desperate to win the $5000 weekly room prize.

Challenge master Shelley Craft wakes the couples at 4am for this challenge, which kicks off at Melbourne's famous flower markets, where she unveils a very rare botanical money tree.

One team has a very difficult decision to make as they can double their winnings by reaching into their neighbours' pockets. The brothers try to keep their room swap a secret from the others.

Scott Cam welcomes game-show host Ed Phillips to the workshop to kick off a big money guessing competition and a magical mystery tour around Melbourne.

A team member is rushed to hospital with an illness, which leaves his partner at home to fend for herself in trying to complete the living room. Her neighbours then have to decide if they can leave their renovations to come to her rescue.

The judges - Neale Whitaker, Shaynna Blaze, and John McGrath - review their decision about the teams' renovations of their roof terraces, and the couples give their views of their neighbours' efforts.

After three days in hospital, Dale finally returns to the block, just in time to help Sophie finish their living room in time for judgement day.

All four teams make a start on their kitchens. Challenge master Shelley Craft welcomes some familiar faces as newly engaged couple Polly and Waz and Josh and Jenna return to the block to set the new teams a wedding challenge.

With kitchens and an extra room to complete, all four teams are under the pump to deliver this week. Lara takes charge of the renovations in her house when Brad leaves the block and impresses site foreman Keith with her new renovation.

Scott Cam sets the teams a workshop challenge to create a dining table from scratch and then turns the tables when they discover their creations will be going on public display in Melbourne's busiest street.

The public get to vote for the winner of yesterday's massive challenge and everybody hopes for a win as their budgets are now extremely tight. And Brad and Lara come up with a novel idea for the splashback in their kitchen island.

The Block's judges, Neale Whitaker, Shaynna Blaze and John McGrath review their decision about the teams renovations of their living rooms and the couples give their views of their neighbours efforts.

With a double-room week and a prize of $10,000 up for grabs, the four teams are in a race to complete their kitchens and their room savers in time for judging.

Lara hits rock bottom when she and Brad run out of money, but Shelley comes to the rescue with a challenge to build a barbecue and potentially save their budgets. The Melbourne Storm are guest judges.

Brad and Lara believe foreman Keith has it in for them when he asks for changes to their outdoor plans. Next-door neighbours Dan and Dani are desperately trying to achieve a garden design with very little budget remaining.

Scott Cam and Shelley Craft take the contestants out for a sports-day challenge. Each couple will represent their house colours as they battle to win much-needed cash for their garden renovations.

The teams are back at the block and hard at work on their exteriors. Once the fences go up between the houses, one team finds themselves completely blocked off. Mike and Andrew finally meet the descendants of the original owners of their home.

Judges Neale Whitaker, Shaynna Blaze, and John McGrath review their decision about the teams' renovations of their kitchens and 'room savers' and the couples give their views of their neighbours' efforts.

After 10 weeks of renovating, the teams are now racing to complete their most challenging room delivery - their gardens and front facades of their homes. The winning team will take home $5000 in gold bullion.

The couples are packing up to move out of the block, but host Scott Cam surprises them with a massive, week-long renovation challenge that could determine the winner of the competition.

Day two of the final challenge, and the scale of the project ahead of them is proving daunting for everyone. Site foreman Keith predicts that time management will prove the downfall of one team.

After three long days of renovating, the teams are battling with each other to deliver the best results. Everyone is relying on the skills learned over the past 10 weeks to get them through.

In the race to the finish line, all four teams are desperate to get an edge over the competition and complete the challenge in time for the special guest judges.

In this final episode of Unlocked the teams reflect on their renovations and prepare for their open for inspections and the all-important auction day.

All four houses go up for public auction. Each team will keep the profit they make over reserve and the team with the highest margin will also win the grand prize of $100,000.