Golden Rain by ian-marke
Danaë was the princess of Argos and daughter of King Acrisius. An Oracle at Delphi warned Acrisius that Danaë would give birth to a son who would one day kill him. Alarmed by this prophecy, Acrisius had a tower of bronze built to imprison his daughter and thus prevent all possible suitors from ever approaching her.
But the god Zeus had seen Danaë, was struck by her beauty and desired her. Only Zeus had the power to transform himself and traverse walls of metal. He metamorphosed into a shower of gold and came to Danaë. Through their union Danaë gave birth to a son - the hero Perseus!
Danaë tried as best she could to raise her son secretly in the tower, but eventually Acrisius found out about Perseus. The king wanted to kill his daughter and her child but he was afraid to do so for fear of angering the gods - especially Zeus. So instead, he had a large chest made and Danaë and her son were placed inside the chest. The chest was then cast upon the sea. Acrisius now thought that he was safe, but Zeus saw this cruel act and immediately demanded Poseidon that the sea be calmed. Eventually the chest was washed up upon the shore of Serifos and was found by Dictys who was fishing there.
Dictys opened the chest to find Danaë and Perseus. He took them into his home and looked after them there until Perseus was fully-grown.
Eventually, Perseus did accidentally kill his grandfather, King Acrisius of Argos, thus fulfilling the Oracle's prophecy.