The documentary investigates the enduring appeal of Cadbury's Dairy Milk bar, while across the Channel, Belgian chocolate factory Guylian allows cameras to witness its production line for the first time. Plus, a look inside the Austrian headquarters of Josef Zotter, whose unique factory features a mini cable-car, an eccentrically inefficient chocolate robot and a cemetery for failed bars.

Behind the scenes at the largest chocolate shop on the planet - the London branch of M&M's World, finding out how the store copes with its annual 5.5 million visitors. Plus, a look at a Belgian chocolate factory that churns out 1,000 tons every day, and the work of independent chocolatier and baker Rose Dummer, who has been commissioned to create a chocolate version of Stonyhurst College to celebrate its 425th birthday.

A visit to the home of Toblerone in Switzerland, following the nougat-making process and discovering where the chocolate-maker's triangle obsession came from. Back in the UK, chocolatier extraordinaire Paul is on a mission. He wants to create a show-stopping chocolate sculpture depicting a barman pouring an everlasting bottle of rum to launch a new range of rum truffles - but the path to chocolate happiness doesn't always run smooth.

A tour of the Aldi chocolate factory in Preston, how many revolutions to whip up a Milky Way, chocolate-dipped grasshoppers and locusts, and a life-size chocolate Boris.

At Prestat, owner Nick is proud of his Royal Warrant, but also of the company's place in history as inventors of the chocolate truffle in 1895. Cameras focus on the expertise which makes these chocs fit for a Queen. There's also a profile of Mackintosh's, creators of Quality Street, Rolo and more. Plus, a nostalgic look at the most romantic ad ever, as voted for by the public. Finally, the ultimate chocolate cocktail contest - Cadbury's Roses Strawberry Creams versus Quality Street's purple one.

Examining the story of Fry's, which created the first chocolate bar in 1847, and a look at the sales of dark chocolate which are on the rise. Cameras visit one of the factories that pioneered this sophisticated new wave in the UK, Sussex-based Montezuma. There is also a look at the creation of a near life-size chocolate Elvis.

Food giant Nestlé opens the doors of its Perugia factory in Italy, where production manager Davide looks into the secrets of what is undeniably a labour of love. Chocolatier Prudence Staite has a big challenge ahead, creating a full-blown chocolate replica of a much-loved vintage motorbike for the National Motorcycle Museum in Solihull, as it celebrates its 35th birthday.

A look at the history of rivalry between different brands of chocolate biscuits and a behind the scenes visit to a Norfolk factory that produces 35,000 walnut whips every hour. Plus, a look at how chocolate became a much-needed taste of home for soldiers serving in the First World War, the story of the world's tallest chocolate fountain, and a chocolatier who was challenged to create a sculpture of an ancient Roman god for a festival.

A visit to the Nestlé factory in Perugia, Italy, where the Crunch Bar is made, and the outpost of Barry Callebaut, the biggest chocolate supplier in the world, which is next door. Emma and Mark Baravelli, chocolatiers from Conwy in North Wales, are given a challenging brief - to carve a life-size baby bison for Lord Newborough's 70th birthday - while there's also a trip to Eurochocolate, the biggest chocolate festival in the world.

Cameras focus on the factory producing cinema favourites Poppets, and also explore the history of Milk Tray's iconic selection box. Plus, a look at a giant hand-painted Easter egg, and Milton Hershey's model town of Hershey, Pennsylvania.

A look at Lily O'Brien's factory in County Kildare, a profile of a Willy Wonka collector, and cameras focus on a version of Brighton Pavilion carved out of chocolate. Plus, chocolatier Chris Zammit takes on one of the most intricate chocolate sculptures he's ever made for the launch of a new hotel.

Chocolatier Chris Zammit helps celebrate the launch for a new hotel; the Cadbury Creme Egg has grown in popularity from a 1960s Easter special.

The making of the UK's biggest selling vegan chocolate Nomo, which is free of milk, wheat, eggs, nuts and gluten. Plus, recreating beloved chocolate bars that are no longer made to see if they really are as good as people remember, a food artist who creates sculptures of savoury dishes out of chocolate, and cafe serving juice made out of the waste products from chocolate manufacture.

A look at the history of Swiss giant Toblerone, which was invented in 1908 by cousins Theodor Tobler and Emil Baumann in Bern, Switzerland, and a visit to Bournville, the West Midlands village founded by George and Richard Cadbury for employees at their factory. Last in the series.