Ilmarinen forges the Sampo in Pohjola's smithy after several failed attempts produce only useless or dangerous objects, and Louhi has it fixed inside a mountain vault, guarded closely as the foundation of her land's newfound wealth. Years pass, and after the death of Ilmarinen's wife, the three great heroes of Kalevala, Vainamoinen, Ilmarinen, and the reckless warrior Lemminkainen, resolve that the Sampo rightly belongs to their own impoverished land and sail north to take it back by whatever means necessary.
Using his kantele, a harp whose music can enchant all who hear it, Vainamoinen lulls Pohjola's household to sleep, and the heroes free the Sampo from its mountain vault and load it aboard their ship. Louhi wakes, discovers the theft, and pursues them in the form of a monstrous eagle or bird of prey, catching the fleeing heroes at sea. In the desperate battle that follows, the Sampo is torn loose and shattered, its pieces scattering into the water; most of it sinks forever beyond recovery, though enough fragments wash up on Kalevala's own shores afterward to bring the land a measure of ongoing, if much diminished, prosperity, a bittersweet outcome the epic treats as a genuine victory nonetheless, since Pohjola's monopoly on the great treasure is broken even though nobody now possesses it whole.