Sven is searching for plunder, and is worried about his flank. Scouts report a ford ahead. Advance parties are sent to secure the ford by Offas' farm, but as they come in sight they find Ragnars' men already in position.
There are only a few men, so Sven decides to seize the ford quickly and then leave a small party behind defences to secure his flank.
He will get his revenge.