Behind our craving for vanilla-flavoured ice cream, cakes and chocolate, or for vanilla-scented perfumes, there's a rattling tale of fast money, skulduggery and the precarious fate of an iconic animal.A few years ago, the humble vanilla bean sold for $80 a kilo. Now it's $800. In vividly beautiful, dirt-poor Madagascar, supplier of most of the world's vanilla, that means good times roll.Vanilla is the best, vanilla is the crazy money. No income better in Madagascar - and I think the world! – Yockno, who is swapping tour guiding for vanilla farming.By day, Prisco is a hustler who buys and sells vanilla in the street. By night, in a seedy bar, he sings of his love for the bean, and what it can get him…Girl, come and weigh the vanilla, there's enough for whatever you want! – Prisco's song lyricPrisco is a bit player in a vast vanilla ecosystem. In the vanilla hub of Sambava, brokers plough money into shiny multi-story mansions. In big export warehouses, women sort their way through hillocks of beans. They're frisked before they go home, just in case they've filched any. In rural areas at harvest time, small farmers guard their crops overnight from roaming thieves. If the farmers catch them, justice is swift and sometimes deadly. They can do crazy things to them – Yockno, tour guide and vanilla farmerLong before the tense harvest, there's an operation that demands the utmost delicacy. Each vanilla flower must be hand-pollinated – a trick invented by a 12-year-old slave boy in the 1840s. Using a tiny thorn, Yockno shows reporter Adam Harvey how it's done.So what I do is push this tongue up…. It's all precision – and timing. Each flower is ready for pollination for only one morning each year.…. and I press softly the male to the female. So now it's done.Vanilla is surely sweet for Madagascar's people, but not for its most celebrated characters – the exquisite lemurs popularised by the Madagascar movie. High vanilla prices are putting pressure on the lemurs' habitat as forest is illegally cut to grow the beans.But as Harvey and the Foreign Correspondent team trek deep into the jungle, they discover – to their delight – that lemurs are hanging on defiantly. Our cameras capture them – bamboo lemurs, white-headed lemurs and critically endangered silky safakas, one of the world's rarest mammals – in all their glory.