Ashwamedha Parva, is about how Yudhishthira attempts to revive the economy of the shattered kingdom after the destructive war of Kurukshetra. He decided to perform a sacrifice called Ashwamedha. He amassed wealth by mining in the Himalayas for treasures in the ancient kingdom of king Marutta. He distributed that wealth through the Ashwamedha sacrifice to the public. A sacrifice of grand scale will create jobs and income. As part of this sacrifice, general Arjuna was sent to collect tribute from the kingdoms. During this journey he met his long lost sister Duhsala in the kingdom of Sindhu and also his long lost son Vabruvanaha ruling at Manipura.
Arjuna meeting Duhsala, the sister of Duryodhana and queen of the Sindhu kingdom in the battle field. Duhsala was thus Arjuna's sister too.