Chapter 3: The Lake.
Grendel fell into the icy water, and tumbled as he was dragged through the current, his head broke the water and he forced a stinging breath in. Then, he was back in the water, he tumbled and banged his head off a rock, then, blackness.
He awoke just as the descent into the Whiterun sewers began; on the way down he hit more rocks and other obstructions. Once he reached the slower waters of the sewers he was able to find his feet and steadied himself. Grendel stood and scanned the area for Vilkas. The sewers turned off to the right a short way ahead of him. That's where he saw Vilkas' unconscious body; it was being prevented from traveling any further by a huge pile of rocks from a recent cave in. A group of Skeevers had gathered around the unconscious man. They were all covered in scabs and sores; one of them went to take a bite at Vilkas.
"Oh, no you don't!" Grendel roared, all of the Skeevers looked up, Grendel drew his sword. The Skeevers charged at Grendel, who smiled and said "Fus, Ro, Dah!" the Skeevers were thrown back, some braking their skulls on the rocks as they fell, one however didn't go more than a foot backwards. Taking Grendel by surprise, this Skeever bit straight through the armour he was using to protect himself. He felt an immense amount of pain in his left shoulder. The Skeever was too close to use the sword on, so he sheathed it, and brought out a Dwarven dagger, using it to stab the Skeever repeatedly until after a while it fell off, dead.
Another two charged at Grendel, he brought out his sword and faced the blade at one of the Skeevers. Thrusting it wildly, he hit the Skeever in the face, right between the eyes. Then as the other one leapt at him, he stabbed that one too. All the Skeevers were dead. Grendel went to check out Vilkas' body.