The story of "Beowulf" is a tale of a Scandinavian warrior, Beowulf, who offers to eliminate the monster Grendel as payback for a favor the Danish King once did for Beowulf's father. Grendel has been terrorizing a Danish kingdom by invading its prized banquet hall and eating its residents. After Beowulf kills Grendel, Grendel's mother seeks vengeance, and Beowulf must defeat her as well.
"Beowulf" is an epic tale that was told orally for many years before it was written down. Many of the characters in the story are actually historical figures from the 6th century CE, though it is not known exactly when the story originated. Although Beowulf himself is Scandinavian, the story was first written in English and is unique among epics because it applies Anglo-Saxon ideals of the time to a story that is deeply rooted in Scandinavian culture, which was very different than that of the Anglo-Saxons.
Scholars doubt that the "Beowulf" that is now canon of English literature resembles the original tale of oral tradition, but because there is nothing on paper prior to 700 CE, it is impossible to know. "Beowulf" is also widely studied for its early example of heroic code, a system of values followed by warriors.