Here, I'm taking a step back from the facts to look at how the news of Napoleon's return reaches Burke in Burke at Waterloo. Burke has been attached to the Belgian Light Hussars, whose colonel, Prince Ferdinand, has just learned that Napoleon is back in France. Ferdinand was a a real person and his response is fairly typical of the way the news was received. Legrand, the spy they are looking for, is fictional, but there is no doubt that Napoleon had agents preparing for his return throughout France.
The prince, usually so urbane, was agitated and leapt to his feet as soon as Burke entered his office. ‘Have you heard, Major?’
‘I've heard nothing, your Highness.’
‘We're keeping it quiet for now, but we'll have to make an announcement later today. Bonaparte is back in France.’
It seemed incredible, but it had happened. Bonaparte had slipped away from Elba with around six hundred men from the ceremonial guard that the Allies had allowed him to keep. Six hundred men should have posed no threat at all, but as soon as he landed in France disaffected soldiers from the French army started to join him.
‘By now he has thousands of followers!’ Prince Ferdinand was pacing agitatedly behind his desk. ‘He is advancing on Paris! Mon Dieu, the Devil has escaped from Hell and returns to threaten our peace again!’
‘Legrand knew.’ Burke, not thinking, had spoken aloud to himself, but the prince seized on his words. ‘Yes, Legrand and all the other Bonapartists. This escape from Elba was not some spontaneous adventure. It was planned. His agents in France knew it was coming. And now one of the most dangerous is here in Belgium!’ He stopped his pacing and faced Burke. ‘You have to find him!’
And here's a picture of Laura wondering why she let me loose on her rather lovely pages.