Isis is the fourth of five children of the Earth God Set and the Sky Goddess Nut Osiris, Horus, Set, Isis, and Nephthys.
As a young woman Isis wished to increase her magic powers and to do this she devised a plan. Isis tricked the Great God Ra into giving her his secret name.
Isis obtained some of Ra’s saliva and by mixing it with dust Isis made an invisible venomous snake and by saying certain words of power over it She made it bite Ra as he passed by.
Ra was poisoned and not knowing the nature of his wound and being weak and about to die he was unable to heal himself. Isis offered to heal Ra if he gave her his secret name. Ra agreed thus giving Isis his knowledge and magical power. Isis used words of power to remove the poison from Ra’s body and he recovered.
Isis later married Osiris and when Seb and Nut abdicated the throne of Egypt, Isis and Osiris took over rulership. Osiris King of the Earth, became a kind and gentle ruler and was loved by his people. He taught them agriculture, gave them laws to live by and showed them how to worship the Gods. After civilising his people Osiris journeyed to Memphis leaving Isis to rule for him. Isis ruled Egypt and was equally loved by the people as she too ruled justly and fairly.
Osiris’s brother Set was jealous and wanted the throne for himself. Whilst Osiris was away, Set plotted against him. Set and his 72 followers devised a plan. Set secretly obtained Osisris’s measurements and had a magnificent chest made that would fit only Osiris. Set then invited Osiris to a banquet and offered the chest to anyone that would fit into it. Osiris suspecting nothing and trusting his brother, laid in the chest.
Set quickly nailed the lid shut and sealed it with lead to make sure Osiris couldn’t get out. Set then along with his fellow conspirators threw the chest into the River Nile, and by doing so claimed the throne as his own.
The chest eventually washed up at Byblos and a Tamarisk tree grew around it. The Chest containing Osiris’s body was found when the tamarisk tree was cut down to make a pillar for the palace of the Phoenicia King of Byblos.
Isis set out to find the body of her beloved husband Osiris. The search took her to Phoenicia where she met Queen Astarte.
Astarte not recognising the goddess hired her as a nursemaid to her infant son. Isis became very fond of the young boy and decided to bestow him with immortality.
Part of the ritual was to hold the baby boy over a fire. The Queen entered the room and seeing her son in the middle of the fire instinctively pulled the child from the flames thereby undoing the magic of Isis that would have made her son a god.
In explanation Isis revealed her identity and told Queen Astarte of her quest to find her husbands body. Astarte realized the body was hidden in the Tamarisk tree in the centre of the palace and told Isis where to find it.
Isis proceeded to bring Osiris back to life. By using magic words taught to her by Thoth she created light with her hair, turned herself into a kite [in some stories she is portrayed as turning into a sparrow hawk] and with the wind from her wings brought Osiris back to life long enough to conceive a child by him. Isis hid the chest containing Osiris body in the swamps belonging to Buto the cobra goddess. She remained with Buto until her son Horus was born.
Set refused to give up the throne and whilst hunting one day he found the chest containing Osiris’s body. And while Isis was away Set had Osiris’s body cut up into 14 pieces and scattered them throughout Egypt. When Isis returned she was grief stricken and immediately began her search for the parts of her husband Osiris. She found all the pieces apart from Osiris’s penis which had been eaten by a Nile crab.
With the help of her sister Nephthys, Isis joined the body parts together and fashioned a new penis out of clay. Along with Anubis, Thoth [Lord of Divine Words], and Horus, Isis performed the first rites of embalming and the rite of rebirth giving Osiris eternal life. Osiris then ascended to Duat the abode of the dead where he became Lord of the Dead. Osiris being a good husband and father often came to look after his wife and son.
Isis hid her son from Set, again in the swamps of Buto, until Horus was strong enough to avenge his father. To make him strong Horus was exposed to many dangers. He was attacked by wild beasts and poisoned by scorpions. Always the magic of Thoth and Isis saved him. As he got older, Osiris came to teach him how to use weapons, so that Horus could eventually claim the throne which was his by birth and take his revenge upon Set.

bravenet.com