Éomer wants to return with all speed to Edoras to report to his uncle, King Théoden.
'We have to return to Edoras at once. I need to report to the King that Fastred is refusing to move his people across the Entwash. We simply do not have the riders we would need to effectively defend them here. In West Rohan we will have a better chance of protecting the people.
'Come with me to Edoras, ${PLAYER}. We will sort this out with my uncle Théoden.'
Éomer wants to ride to Edoras with you to consult with King Théoden about Fastred's refusal to move his people across the Entwash.
Horn is at the Entwade crossing, in the Sutcrofts.
The unthinkable has happened: Éomer has been imprisoned at the command of the King and you have been ordered never to cross the Entwash under pain of death.