King Hrothgar, the ruler of the Danes, is troubled by the rampages of a demon named Grendel. Every night, Grendel attacks King Hrothgar's wealthy mead-hall, Heorot, killing Danish warriors and sometimes even eating them.
Hrothgar was a great warrior in his time, but now he's an old king and can't seem to protect his people. Fortunately, a young Geat warrior named Beowulf travels to Heorot Hall from his own lands overseas to lend a helping hand—literally.
After explaining that he owes Hrothgar a favor because Hrothgar helped out his father, Beowulf offers to fight Grendel himself. King Hrothgar gratefully accepts his offer. The next time Grendel attacks Heorot Hall, Beowulf is waiting for him. Choosing to fight Grendel in hand-to-hand combat, Beowulf wrestles the demon into submission and eventually tears off his arm at the shoulder. Mortally wounded, Grendel flees into the wilderness and dies. Beowulf, Hrothgar, and their followers throw a wild party to celebrate. Hrothgar also gives Beowulf many presents and treasures to reward him for his heroic defeat of the demon.