Beowulf and his men were swiftly sailing over the high thrashing waves to Danes' land to help Hrothgar. The waves smacked against the boat knocking the men and Beowulf off his feet. The waves were so strong they were pushed back 100 feet. The wine-dark sea whistled at dawn while the men and Beowulf were sailing.
Swift footed, Grendel came from the marsh waiting for the men to fall asleep drunk. Once they had fallen asleep, Grendel snapped the door open and rushed angrily to the threshold. He snatched up the first man and ripped him apart with his teeth with blood all over the mead hall. When Beowulf jumps up, like he's the strongest man on earth. He finally killed Grendel with his bare hands ripping off his arm and keeping it as a trophy. He is the happiest man alive.
Once Grendel's Mother had figured out that her son was demolished by a man, she seeks revenge. The extremely powerful Beowulf hears that Grendel's Mother is seeking revenge on the man that had taken Grendel's life. After they go to her dangerously dark lair, he almost gets his life taken away, but he was going to demolished her, like he did Grendel. He had gotten back to top of the lake when the sword that was used to kill the mother was dripping blood and disappearing like ice.