Beowulf, with fourteen companions, sails to Denmark, to offer his help to Hrothgar, king of the Danes, whose hall (called " Heorot ") has for twelve years been rendered uninhabitable by the ravages of a devouring monster (apparently in gigantic human shape) called Grendel, a dweller in the waste, who used nightly to force an entrance and slaughter some of the inmates.
In the vault he finds the corpse of Grendel; he cuts off the head, and brings it back in triumph.
There are similar alternative possibilities with regard to the explanation of the striking resemblances which certain incidents of the adventures with Grendel and the dragon bear to incidents in the narratives of Saxo and the Icelandic sagas.
When all but Beowulf are asleep, Grendel enters, the iron-barred doors having yielded in a moment to his hand.
Grendel, though mortally wounded, breaks from the conqueror's grasp, and escapes from the hall.