Demeter and the Abduction of Persephone
One of Demeter;s children was Persephone, also known as Kore, which she created together with Zeus, the King of the gods. What Demeter didn't know was that, by the time Persephone was born, Zeus had secretly promised her to his brother Hades, the god the Underworld.
One day, when Persephone was still very young, she went out to play with her girlfriends and was spotted by Hades who immediately felt bewitched by her charms. Hades was just waiting for the right moment to come and, when he saw Persephone picking some flowers, he seized the opportunity, opened the earth and abducted her to his Underworld. Persephone started screaming so loud that her mother Demeter heard her painful cry and went to the valley to see what was going on. She started searching carefully but she couldn't find her beloved daughter anywhere. So she went on asking anywhere she was meeting on her way, but not one seemed to know where Persephone was.
Finally, Demeter decided to visit Helios, the wise Sun god, who happened to know the story, and asked him for advice. Helios was a kind god and felt mercy for the mourning mother, so he revealed to Demeter the whole truth. Nine days passed without change, driving Demeter to despair. She could neither eat, nor drink, nor could she sleep and nothing was blossoming on earth, leaving humans and animals with no food.
Zeus disliked this situation and decided to send his messenger Hermes to the Underworld to talk to Hades. Hades was not willing to set Persephone free, but, after all, it was the king talking to him, so he was obligated to obey. So he gave Persephone to Hermes, who took her up on his golden chariot and brought her back to her mother Demeter.
Demeter was delighted to see her daughter again and cried uncountable tears of joy, brining this way fertility back to earth. She was hoping to keep her daughter close to her forever, but during her stay with Hades, Persephone had eaten six pomegranate seeds and was therefore chained to stay in the underworld for four months of the year.
This way, the seasons were created in the upper world. All the time Persephone was with Demeter, Demeter was so full of happiness, that the sun was shining and everything was blooming. All the remaining time, when Persephone had to return to the Underworld, Demeter was in grief and nothing could grow... this was the time winter set out in the world.