Episode 421 is available via various sites
Naruto and Sasuke finish their conversation with the Sage of 6 paths who gives them his power.
Naruto finds he now has all 9 tailed beasts in side him.
brief shots of Karin and Sakura worrying about their guys.
Guy finds that his last attack wasn't enough, he activates Night Guy A massive dragon shaped attack that actually nearly kills Madara.
Madara trus to finish guy off but Naruto saves him.
NExt Episode 422 those who will Inherit
looks like brief filler.