Kerry welcomes the listeners to 'Matrix' - a new interactive exhibition about The Great Fire of London. The listeners will be working in role to test Matrix and report back, before it opens to the public. The children put on their virtual reality - 'VR' - helmets. With the helmets on the children can see and hear the sights of London in the Autumn of 1666. Kerry switches on the interactive experience and the children's adventure begins. They must navigate the streets of London looking for safety. Along the way they must undertake three additional challenges: i) they must offer assistance if asked to do so along the way; ii) they must return something that has been lost and iii) they must speak with a king.