Gregg Wallace is in the UK's city of chocolate, York, exploring how the Nestle factory makes more than 8 million bars of chocolate every day. The bar he's following is the one packed full of bubbles - the peppermint-flavoured Aero.
Meanwhile, Cherry Healey is in the Berkshire countryside, learning how a cocoa plant quarantine facility is preventing a worldwide chocolate shortage. And historian Ruth Goodman is serving up the bitter history of drinking chocolate.