In the land of the Danes, king Hrothgar and his men where beign terrorized by Grendel, an evil monster for 12 winters.
Beowulf and 14 other men headed from Geatland to Denmark in order to aid the king in defeating the monster.
I am Beowulf, a warrior from Geatland who has come to your aid.
The king tells Beowulf that Grendel comes from a nearby lake where they through all of their waste. Grendel is made of all the waste and rubbish that the Danes leave behind in that lake and it feeds on them in the night.
I will defeat Grendel, but I will do it with out wepons.
That night, the warriors slept in the mead-hall, awaiting Grendel's arrival.