The British expeditionary force
In the spring of 1810 the British and the Dutch were ready. In secret Louis Napoleon had notified some trusted generals, ministers and majors. The Dutch army was sent under false pretences south towards Arnhem, near the new border with France. In Britain an expeditionary force of 50.000 had been prepared. In may the British navy made sure the North sea was clean of French ships and the British expeditionary force landed in Rotterdam. The plan was simple, cross Rhine and march towards Antwerp, to destroy the French navy which was anchored there. From there march south towards Brussels and into France. In the east the Dutch army would try to liberate first Nijmegen and move south towards Maastricht , Liege and Aachen. Hopefully the former allies of Prussia and Austria and maybe even Russia would see an opportunity and rise against France. There was also the hope that the German, Dutch and Flemish parts of France would revolt against their master.
In the beginning the plan worked well. The British crossed the Rhine and quickly reached the recently annexed Dutch city of Breda. From there they moved south towards Antwerp. Here they beat a small French army. The surprise was almost complete, but since Walcheren Antwerp was prepared for the British. After a long and hard battle Antwerp was captured, but the momentum of the attack was gone.
In the east the Dutch army moved to Nijmegen, here too they faced only little resistance. This changed quickly; the French quickly regrouped and while the Dutch army moved south from Nijmegen they were beaten near Venlo. The Dutch quickly retreated towards Nijmegen. The French pressed on and the Dutch army was forced to cross the Rhine again, back towards Arnhem. Here they managed to keep the French army from crossing the Rhine.
Meanwhile Napoleon had figured out what had happened. The various people who where present when he got the news, remembered that they had never seen him so angry. He quickly prepared the French counterattack. A large army was sent to Brussels, where the British marched to after Antwerp. A smaller army was sent to Nijmegen to beat the Dutch.
When the British neared Brussels, the French were already waiting. It was a hard and tough battle, but in the end the French were victorious. The British were forced to retreat. Near Arnhem the reinforced French crossed the Rhine. The Dutch were not able to keep the French south of the river. They moved west towards Utrecht. Meanwhile the British moved north, not able to defeat the French. Soon the British were back in Holland.
There was only one thing that could keep the French of overrunning all of Holland: The Dutch Water Line. The Dutch inundated a large part of country between the Zuiderzee and Zeeland in the south. The French armies were not able to cross it and stopped their advance. Behind the Water Line the Dutch and British regrouped. It was clear they had lost this battle. Neither the Prussians nor the Austrians had joined the British. Meanwhile the French swarmed the rest of the country. All of it was annexed to France and Napoleon vowed to do the same with the rest of it. A large French army glared across the water towards Holland ready to conquer it as soon as possible, but for now it was safe. The kingdom of Holland was free again, but it was a lot less than king Louis had hoped for.