You received the kings authoristion to build a keep. Unfortunately your keep is next to the Malvoisins domain, ruled by two wretched brothers called the Rat and the Pig.
One day a Malvoisin hunting party, led by the Rat rampages through your lands. After attacking and killing some of your retainers you put an final end to the Rat and his men.
Mad of the loss of his younger brother, the Pig swears to take revenge and to kill you.
The Malvoisin forces are a dangerous and well equiped enemy. Better prepare for serious trouble and quickly complete that moat around your motte. Maybe also build that trading post next to the river that you planned some time ago...