At first, Gunther was reluctant to turn against Siegfried, since the hero had helped him win his war and his wife for him. But Hagen managed to persuade his king that it was best for Siegfried to die. It seemed Hagen envied Siegfried's great wealth, power and prowess. Though Hagen was Gunther's best warrior, Hagen was really no match for Siegfried.
First, Gunther would announce false news that Liudeger and Liudegast was going to invade his land again, and was to ask Siegfried for aid. Which Siegfried had readily agreed.
Hagen then went to Kriemhild, to find out if Siegfried had any weakness. Kriemhild, unaware of her brother's henchman of treachery, she disclosed that Siegfried's only weakness was small area on the hero's back, between the shoulder blades. Hagen lied to her, saying that he would protect her husband back in battle. Kriemhild, who was reassured by Hagen's words, told the villain that she would sew a patch on Siegfried's tunic, so that Hagen knows what area to protect.
The day Siegfried was about to set out with the army, Gunther gave another false news that Liudeger and Liudegast had withdrawn all claims to his land. Instead, Gunther invited Siegfried on a hunting trip.
Kriemhild had a bad dream about her husband. She failed to persuade Siegfried to stay with her, rather than go hunting with her brother.
During the long day of hunting in the woods, Siegfried killed a bear. boar, buffalo, oxen and deer with a swordand with the help of his hound. During lunch Hagen had secretly salted the food, to make Siegfried thirsty. Hagen also ensured that the servants left behind the wine.
Hagen challenged Siegfried to a race to a spring beyond the hills. Here, they may drink to quench their thirsts. Siegfried eagerly agreed and told them he would give them a chance by carrying all his equipment