The Hardest Rock in the World

Mitsuki wakes from a dream about the time Log and Orochimaru each tried to win him over, startled that he can dream at all. Over food at the Lightning Burger, he mentions this first dream to his friends, and Boruto is amazed he has never had one. Shikadai and Inojin arrive, the latter carrying a chick that hatched during a poultry-farm mission and imprinted on him. Mitsuki privately likens the imprinting to first meeting Boruto after choosing neither Log nor Orochimaru. Sarada reminds the team they are on security detail for the Five Kage Summit, where the topic of the Ōtsutsuki clan has drawn the former Kage Kakashi, Mei, and A. Darui notes Ōnoki is missing, and Kurotsuchi explains he came with her but slipped away, likely to sightsee.

Bored on watch, Boruto asks Mitsuki for something interesting, and Mitsuki instead asks whether he has ever felt his thoughts were not his own, wondering if his attachment to his friends is like the chick's imprinting, a genjutsu he cannot break. Boruto waves it off, and to lighten the mood shares a riddle his father posed the night before about the hardest rock in the world.

Spotting nearby shinobi, Mitsuki learns they are searching for Ōnoki, which excites Boruto, sure the former Tsuchikage would know the riddle's answer. Ōnoki wanders past, snatches Boruto's drawing of him, and complains it looks nothing like him. He agrees to answer the riddle only if the genin show him around the village instead of dragging him back to the dull summit. During the tour he throws his back out mock-threatening them with Dust Release, yet later uses that same technique to shield a civilian from a falling construction beam before collapsing from the strain. Waking, he briefly mistakes Boruto for Kozuchi, his grandchild who died young.

Ōnoki finally explains that the hardest rock is the unbreakable will of a shinobi. When Boruto and Sarada squabble, he asks Mitsuki about his own will, and hearing that Mitsuki finds it complicated and uncertain, tells him that if he keeps pursuing it, that is the truth. He reveals he had asked Naruto the very same question, meaning Naruto passed it to Boruto without knowing the answer himself. After the group returns Ōnoki, Mitsuki finds the answer satisfying even as Boruto calls it a trick. Home that night, Mitsuki senses an intruder has been there and burns a letter left for him, and the next day two guards at the village gate are struck by Lightning Release.

The episode is part of the Mitsuki's Disappearance arc. A stated detail places Ōnoki at 100 years old per Sarada, though a trivia note points out he would actually be about 94, having been 79 during the Fourth Shinobi World War fifteen years earlier.