The stakes are raised higher than ever in this series of The Apprentice, as this time there is no six-figure salary job on offer. Instead, the sixteen candidates are vying for one life changing opportunity: £250,000 investment to start their own company, with Lord Sugar as their business partner. Lord Sugar wastes no time showing the candidates he means business, using the first task to challenge his potential partners' entrepreneurial skills. Each team are given £250 to invest in fresh fruit and vegetables, and Lord Sugar makes it clear that he expects a high return. Packed off to New Covent Garden Market, the teams race to buy the best produce at the cheapest price and set to work adding value to their haul by making juices, fruit salads and soups, and pasta to tempt London's hungry workforce. With the pressure on to exploit both the lucrative breakfast and lunch trade, it's not long before the tension rises and the blame game begins.

An early morning delivery sends the candidates into the fast-paced world of technology. Lord Sugar challenges the teams to think big and go global as they must design, launch and promote a new mobile phone application. In the battle for downloads, the teams must create a mobile app and pitch it to three influential technology websites to become 'App of the Day', as well as attempt to convince a huge crowd of bloggers and software experts at a major gaming fair to support the application and increase downloads. With their apps downloadable for 24 hours, a dramatic result leads to a fierce boardroom battle, and one more candidate faces Lord Sugar's immortal words: 'You're fired'.

The candidates are called to meet Lord Sugar at London's famous Savoy Hotel to be briefed on their next task. Following a 220 million pound refurbishment, the hotel requires a number of last-minute items prior to its grand reopening. The business hopefuls have nine hours to source ten products, and their powers of negotiation are pushed to the limit as they attempt to track down everything on the hotel's unusual shopping list and purchase them at the lowest possible price. Nick and Karren watch on as the candidates get increasingly desperate in their attempts to find quality items at bargain prices. With the deadline looming, tension reaches fever pitch as last-minute deals are struck. Both teams are faced with a dash to the Savoy to have their purchases inspected by the scrupulous eye of the hotel's general manager. Missing or incorrect items are subject to penalty fines, and this leads to a dramatic result in the boardroom.

Lord Sugar gathers the candidates under the statue of Aphrodite at the British Museum, and reveals their next task: to set-up beauty treatment businesses in Birmingham. At the briefing, he re-balances the teams and personally appoints the project managers. The British beauty industry is worth 14 billion pounds annually, with the best margins in hands-on treatments, so Lord Sugar demands both teams offer these and sell cosmetic products off the back of them. After a choice of professional treatments have been offered to the teams, followed by a short wrangle over total body spray tan, the teams choose two treatments each and get down to some hands-on training. But one of the boys feels that touchy-feely beauty challenges his masculinity, and could worry his girlfriend. Under the watchful eye of Nick and Karren, the teams take their choices to Birmingham. One team goes for the city centre, while the other chooses an out-of-town mall.

In a pre-recorded briefing via a giant screen flanked by Karren and Nick, Lord Sugar has called the candidates to an advertising agency. Their task will be to create, brand and pitch a new pet food. But before they start Nick has a message from the boss - once again he picks the team leaders. One team chooses dogs, the other cats. Both teams split - one half to Lincolnshire to create the food, the other half staying at the agency to name and brand the product. Supported by Britain's biggest pet food manufacturer it looks like a breeze, but soon the teams are making some fateful decisions, sweeping aside advice from pet-loving focus groups and inventing product names so leftfield that even teammates can't understand them. Professional packaging for their products restores confidence momentarily, but the next job - to make commercials - plunges the teams into more confusion as they try to get creative.

Alan Sugar calls the candidates to a rubbish dump, and challenges them to form junk-collection businesses. One half of each team has to haul the rubbish themselves while the others offer quotes on big clearances. Profits prove hard to come by with Cockney scrap dealers and quick-witted builders giving them a run for their money, and one project manager is reduced to tears by the grueling work.

The teams are called to gleaming offices in Fleet Street, home to London's oldest newspaper district. Lord Sugar informs the candidates they'll be creating and publishing a free magazine. But first he shuffles the teams, appointing the project managers. Free magazines earn money by selling advertising, but advertisers only buy space in titles with a surefire market. As such, the teams must choose a hit subject, produce appropriate editorial content and convince advertisers they will reach a big audience. As Karren keeps notes, one team is led downmarket by their editor with a low-brow lads' magazine. The other team, accompanied by 67-year old Nick, goes for the oldies market, and on the way comes up with some patronising names (causing raised eyebrows from Nick!). But despite some research with sprightly over-sixties, it soon descends into stereotypes. Karren winces as the lads' mag embraces innuendo and photoshoots get racy.

The venue for the candidates' latest briefing is St Pancras International. With the next Eurostar about to leave, there is just time for Lord Sugar to brief and re-balance the personnel, and then it's off to Paris for half of each team. The others must stay back and choose some new British designs to sell to the French. It is a classic export task, with Lord Sugar on the lookout for proven ability to do business abroad. While the candidates in Paris arrange sales appointments for tomorrow, the London-based groups are treated to quirky products by entrepeneurs wanting a slice of the French market. There's everything from toys to top-end bikes. It is immediately clear that some of Lord Sugar's budding business partners know very little about the French, and even less about what they will buy. To help, he sets them up with a major French retailer, but the teams must fix all the other pitches. Street-based research gets lost in translation.

The candidates are enjoying their day off when Lord Sugar turns up at the door. Suddenly it's down to work after he tells them to make, brand and pitch a new type of upmarket biscuit. Project managers get picked (in one case reluctantly) and then it's time for the teams to split up, with half off to a biscuit development lab in Swansea. The teams have two days to get the baking done and packaging designed. In Wales there are sharp elbows in evidence in one team as two of the candidates vie to get their idea made, whilst the other team goes straight for an after-school treat. The ultra-competitive team's focus group munches its way through lots of crunchy offers without a favourite emerging. No-one likes ideas suggested by fellow team members and in the end the decision is a compromise. On the other team, the branding for kids ends up losing precision and no-one can understand its selling point. Hard work in the development lab produces professional looking biscuits.

Called to a north London wholesale warehouse, the teams are met by a nostalgic Lord Sugar, who tells the teams that it was from places like this that he started out buying low to sell high. He gives both teams a pallet carrying 250 pounds' worth of wholesale goods. They must find out what sells best, then re-invest in those products. It is a simple exercise in following the money and increasing sales. The pallets contain cheap nodding dogs, pricey pressure washers, duvet sets, cut-price sunglasses, brollies, watches and more. The prospects for the task look good, and there are quick volunteers for the team leader roles. They have the whole of London to sell to: street markets, houses door-to-door, offices and maps to help find more. The trick is to match the products to the potential market, but some get it badly wrong, taking tacky stuff to snobby areas, or high-priced goods to East End pound shops. For some selling comes naturally, but for others it's a humiliating struggle.

As this year's series of The Apprentice draws to a close and the tension mounts, this programme profiles the remaining five candidates. Revealing the true stories behind their super-confident egos, we discover what really makes these budding business men and women tick. Family, friends and former bosses, along with Lord Sugar's trusted aides Nick Hewer and Karren Brady, discuss the strengths and weaknesses of the final five personalities as they vie for the prize of a quarter-million pound investment and a partnership with Lord Sugar.

At a shopping mall in the City of London, Lord Sugar points out to the teams the wide range of successful fast-food chains and tells them to invent their own outlet, develop a unique cuisine, open it to the public and pitch the concept to him and experts from the fast-food industry. The teams get two brand new sites in the centre of the West End to turn into protoype fast-food outlets. One team goes for Mexican meals, the other for British pie and mash. Both teams split - one half to cook, the other to make the branding match the concept. The Mexican restaurant gets called Caracas because it sounds like maracas, while the pies get named after historic Britains; except that, once the branding has been done, Nick casts doubt on the British credentials of Christopher Columbus.

After eleven tasks, it's finally time for Lord Sugar to choose his business partner. The four finalists each have to face a gruelling interview process on their own. There is nowhere to hide as each of them is grilled by four of Lord Sugar's trusted business colleagues and advisors. Each candidate will also have their business ideas tested to destruction, as their plans for their business with Lord Sugar are put under the microscope. It's the ultimate test of character, as every aspect of their personal and professional lives is scrutinised and judged by the influential interviewers. After they have made their assessments, Lord Sugar's four advisors feed back their opinions and explain their verdicts to him in the boardroom. As the candidates take their turn to plead their case, three will have their dreams shattered as Lord Sugar delivers his final ruling on who will become his business partner.