When Yazid I, the third Umayyid Caliph, took power in 683, an increasing number of Muslims were dissatisfied with their government, and the hereditary succession of men they saw as bad muslims and rulers.
The rebellion which broke out in 686 CE was supported by the faction of Muslims. Al-Mukhtar led the rebellion, which was launched from Kufa, in present-day Iraq. It is rumored that he was rebelling on behalf of Ali's son Husayn ibn Ali, after he was martyred in Karbala by the army of Yazid. Al-Mukhtar was in prison whilst the tragedy of Karabala was taking place, or so it is said in his defense as he was not present but was later hailed as a supporter of Hussein. After he was out of prison, he found out about what happened in Karbala. So he set out to avange the grandson of Mohammad's death.
Al-Mukhtar struggle was not a revolution for power. It was for the revange of killings of house holds of Muhammad. He found and killed each and every person had eiher killed or had helped in the killing of house hold of Muhammad.
At a moment he was sentenced and was about to be killed by a governor of Yazid(Laen). That time he said that I have not finished a task which Imam Ali has said that I will be doing, So, no body can kill me and in an interesting sequence he was saved.
For reference read MUKHTARNAMA