Recently, we saw the end of the battle between Madara vs Guy in the latest Naruto Shippuden 421, on top of this we saw a number of other extra bits where Hagoromo met with Sasuke and Naruto in their own consciousness and gave both of them power. In turn, this allowed for Naruto to save Guy and allow for a whole new battle to begin: Naruto and Sasuke vs Madara Uchiha!
Naruto Shippuden 421 see’s Naruto and Sasuke talking to Hagoromo, they tell him their desire while he gives them both Indra and Ashura’s Ninshu to allow them go try to defeat Madara before he can attain Kaguya’s power. All while Guy battles against Madara, unable to make a significant dent on him, thus he uses his most powerful technique, Night Guy releasing all his power. He’s about to die when Naruto arrives and saves him.
Naruto Shippuden 420 (blaze up) see’s the continuation of Madara vs Guy, as Guy releases his full potential with his Evening Elephant crushing all moves and defenses Madara has to offer, all while Madara not quite fighting back. At the same time, Naruto wakes up to an stranged named Hagoromo Otsutsuki revealing to him that he is his son’s, Ashura, incarnation.