The Sensex opened with a positive gap of 109 points at 10,591. After moving somewhat higher the index soon plunged into the negative zone to a low of 10,185 - down 297 points from the previous close.Bargain hunting at lower levels saw the index recover and rebound into the positive zone. The index, thereafter, swung in and out of the positive zone till late noon deals.A fresh round of buying in the last session saw the index rally to a high of 10,859 - up 674 points from the day's low.The Sensex finally finished with a gain 3.2% (341 points) at 10,823.