Once upon a time, Odin, Loki and Honir wandered the world. When hunger began to bother them, they saw a herd of oxen in a deep valley. They killed one of them and Loki started roasting the meat. Imagine their surprise, when the meat remained bloody and red after a long time, not yielding to the heat of the fire. They understood, there is a spell at work here, but they couldn't find out, who dumped him.
At one point a huge black eagle sat on a branch. He laughed, seeing hungry gods and said, that without his help, the roast will never be ready. He promised to help them, if they give him a part of the supper. The Aesir agreed. The eagle flapped its enormous wings and ignited such a powerful and hot flame, that the meat was soon ready to eat. Then the eagle flew down and began to feed. He ate very voraciously, so that in a short time from the whole ox there were only remnants of meat left on the spine and shoulder blades.
The gods were furious, seeing such greed, after all, they did not want to go to bed hungry. Loki grabbed a piece of the stick and struck the eagle, wanting to chase him away. The bird took flight, pulling Loki with him, for the stick is stuck to the hand of god and to the feathers. So the bird lifted him up in the mountains and began to drag him along sharp ledges, mountain pine bushes and thorns, laughing and mocking the wretch. Loki pleaded for mercy, but the cruel opponent cared for no spells. In the end, he promised to release him, provided, that will lure Idunn out of Asgard. Here he took his true form of a giant. Loki was even more scared, because in him he recognized Thjazi - the Storm Giant, the most powerful of Thurs. In fear, he promised to comply with the request and was released.
Back in Asgard, he told the gods a clever story, explaining his deliverance. Some time passed and Loki started talking, that twin apples like these grow near Asgard, which Idunn gives out to the gods every morning. Finally he persuaded the goddess, to take her wonderful basket and go with it to the place, in which the same apples were supposed to grow. As soon as they hid in the forest, Thjazi flew up and kidnapped Idunn, taking it to his seat in Thrimhejma.