Sophie’s flute was made of gold and many people wanted to have it for themselves. But her flute was attached to her life so that if she lost it she would die. In a bid to preserve her life, she had to cast a spell on anyone making an attempt to steal the flute. Many have tried and failed.
Loki in an attempt to take the flute, stole his father's cloak and disguised as his father, he went to Sophie’s lair. He succeeded in taking the flute after a tussle with Sophie, but the effect of the spell started working on his father. While Sophie lay dying as a result of the loss of the flute, Loki sped away with joy as the flute hold the secret of the den of Indima.
But what he did not know was that only the rightful owner of the flute can enter into den. Getting there he saw Thor the ruler of the hordes come with vengeance to defeat him. Thor was able to retrieve the flute but since Sophie, the rightful owner was dead, he left the flute to the dust in the den of indima.