Pritha was the daughter of King Surasena, given to his childless cousin Kuntibhoja. That’s why her name is Kunti. Sie was the sister of Krishna’s father Vasudeva. She married Pandu, they were childless. Kunti had gotten a mantra from sage Durvasa, with this mantra she could call every God and father a child with him.
In 16 chapters the Mahabharata is told from Bharata to Pandu. The link is the first chapter. All chapters are found in June 2016.