King Hrothgar of Denmark, a descendant of the great king Shield Sheafson, enjoys a prosperous and successful reign. He builds a great mead-hall, called Heorot, where his warriors can gather to drink, receive gifts from their lord, and listen to stories sung by the scops, or bards. But the jubilant noise from Heorot angers Grendel, a horrible demon who lives in the swamplands of Hrothgar's kingdom. Grendel terrorizes the Danes every night, killing them and defeating their efforts to fight back. The Danes suffer many years of fear, danger, and death at the hands of Grendel. Eventually, however, a young Geatish warrior named Beowulf hears of Hrothgar's plight. Inspired by the challenge, Beowulf sails to Denmark with a small company of men, determined to defeat Grendel (Waterhouse, pp. 26-39).
Hrothgar, who had once done a great favor for Beowulf's father Ecgtheow, accepts Beowulf's offer to fight Grendel and holds a feast in the hero's honor. During the feast, an envious Dane named Unferth taunts Beowulf and accuses him of being unworthy of his reputation. Beowulf responds with a boastful description of some of his past accomplishments. His confidence cheers the Danish warriors, and the feast lasts merrily into the night. At last, however, Grendel arrives. Beowulf fights him unarmed, proving himself stronger than the demon, who is terrified. As Grendel struggles to escape, Beowulf tears the monster's arm off. Mortally wounded, Grendel slinks back into the swamp to die. The severed arm is hung high in the mead-hall as a trophy of victory.
Overjoyed, Hrothgar showers Beowulf with gifts and treasure at a feast in his honor. Songs are sung in praise of Beowulf, and the celebration lasts late into the night. But another threat is approaching. Grendel's mother, a swamp-hag who lives in a desolate lake, comes to Heorot seeking revenge for her son's death. She murders Aeschere, one of Hrothgar's most trusted advisers, before slinking away. To avenge Aeschere's death, the company travels to the murky swamp, where Beowulf dives into the water and fights Grendel's mother in her underwater lair (Abrams, pp. 29-32). He kills her with a sword forged for a giant, then, finding Grendel's corpse, decapitates it and brings the head as a prize to Hrothgar. The Danish countryside is now purged of its treacherous monsters.
The Danes are again overjoyed, and Beowulf's fame spreads across the kingdom. Beowulf departs after a sorrowful goodbye to Hrothgar, who has treated him like a son. He returns to Geatland, where he and his men are reunited with their king and queen, Hygelac and Hygd, to whom Beowulf recounts his adventures in Denmark. Beowulf then hands over most of his treasure to Hygelac, who, in turn, rewards him.
In time, Hygelac is killed in a war against the Shylfings, and, after Hygelac's son dies, Beowulf ascends to the throne of the Geats. He rules wisely for fifty years, bringing prosperity to Geatland. When Beowulf is an old man, however, a thief disturbs a barrow, or mound, ...