Wagner Group captures headquarters of the Southern Military District and the building of the Ministry of Internal Affairs in Rostov, the headquarters of Russia's base of operations for War in Ukraine
Everyone in Wagner was about to be conscripted into the regular Russian Army as the latest in an ongoing power struggle between Wagner's boss and the Russian MoD. So to avoid losing his private army, the boss has stepped up the power struggle to an attempted coup, basically.
Having Russia and its nukes controlled by a mercenary doesn't seem like much of a win, tbh. Not to say Putin's better, but I see more of a lose-lose, myself.
The head of Wagner was unhappy with Russian military leaders and thought he'd take matters into his own hands as Putin was going to support him. Putin did not. Now there are 10,000 men heading to Moscow.