Mitsuki's Friend Boruto: Naruto Next Generations : Season 1 Episode 80

Instead of returning home with Boruto, Mitsuki stays with Kokuyou. During this time, Sekiei becomes sick and declines. To recover, Kokuyou returns to his comrades. During his absence, Sekiei asks Mitsuki to teach him what it means to be human. Meanwhile, the Fourth Tsuchikage Kurotsuchi, who had been visiting Ohnoki, her ailing grandfather, is attacked by mysterious assailants.