Daughter of Earth goddess Demeter, she was picking flowers with a clutch of nymphs when the earth split open and Hades grabbed her and whisked her off to the underworld, there to be his battered consort.
Angry Demeter gave the nymphs what-for by changing them into Sirens and then she set about searching for Persephone. This distracted her from her earthly duties, so the fields fell fallow, which did not sit well with Zeus. (Did I mention Zeus was Persephone's father? No? It hardly matters.) He sent Hermes to hell on a rescue mission.
Hades gave in and let her go, but on the condition she eat no infernal thing. Then he handed her a pomegranate. Now, everyone knows a pomegranate is a hell of a thing to eat, so Persephone, although she returned to earth the prodigal daughter, was bound by her contract to return every winter to serve as Queen of the Underworld. The earth would thus sleep in those months, but more importantly, people learned to go to warm, sinful places when it turned cold outside.