A beast named Grendel attacks Herot Hall, where years of celebration had taken place. He kills many men.
Beowulf, the hero of this story, owes a favor to the king. He kills Grendel and takes his arm as a trophy.
Grendel's mother wanting her son's death to be respected takes back her son's arm. Beowulf finds her and kills her. Instead of taking the arm back he takes Grendel's head.
After killing Grendel's mom the celebrations in Herot Hall resumed. Herot was at peace for 50 years.
A common thief awakens a dragon who had been guarding a cave full of gold. Beowulf, now old, attempts to defeat the dragon. One of his men has to help him defeat it.
Beowulf and the dragon die during this battle. Beowulf asks Wiglaf (the man who helped him defeat the dragon) to bring him gold from the dragon's cave. He also asks that a tower be made in his name, so that he would not be forgotten.