Beowulf arrives at Herot to help King Hrothgar and his people, who have been terrorized by the monster Grendel for 12 years. Beowulf vows to kill Grendel with his bare hands. That night, Grendel attacks the meadhall but Beowulf engages him in an intense battle and tears off his arm, causing Grendel to flee and die. However, Grendel's mother is still a threat, so Beowulf agrees to slay her in her lair beneath a nearby lake.