During her first days the Brusilov Offensive went excedingly well, inflicting important casualties to the Austro-Hungarian army and taking back significant grounds. The austrians where in full retreat and some began to hope or fear that the southern part of the Central empires eastern front would crumble completely.
Things, however, started to go astray when the planned offensive by the russian army group on his northern flank, designed to prevent the germans to intervene in force to save the Austro-hungarians, wasn't launched. 17 german divisions where transfered to Galicia and helped the austrians stop the russians at last.
What if the attack in the northern part of the eastern front was launched, as Brusilov wanted. How badly could have things turned out for the Central empires here? How well could the Russians have done? What would be the effects on the rest of WWI?