Prometheus witnesses humanity and what they go through and wishes to give them fire and teach them stuff so they can strive.
Prometheus goes to Jupiter and begged him to give men fire but Jupiter wouldn't even give them a spark.
Prometheus still gave mankind fire and taught them many stuff like how to build houses to strive and bring a new golden age.
Zeus asked his blacksmith to make a woman. The blacksmith did and the mighty folk gave her many gift to make her the perfect woman. They also gave her a box not to open.
Mercury gave Epimetheus the woman made, Pandora, as his wife. Prometheus doesn't trust a gift from that tyrant, but Empimetheus fell in love with her at first sight. Pandora is curious and wants so badly to open the box
Soon the temptation got the better of her and she opened the box and with that horrible things ravage on humanity and the precious humans Prometheus tried to help were attack by these spirits. These spirits were mankind's punishment. Pandora manged to close the box before the last spirit, the strongest one, to come out and if he did mankind would die out.