Answer:
Beowulf, who is the prince of the Geats comes to Heorot to help King Hrothgar defeat a monster that has been terrorising his kingdom.
He defeats the monster Grendel, but Grendel's mother comes for revenge and Beowulf goes underwater to fight her too. He realises his weapons cannot hurt her and finally uses a giant sword off the wall to kill and decapitate her.
