"Unevolving Species" (進化無き種, Shinkanaki Shu, Viz: Without Evolution) is chapter 700+6 of the Naruto Gaiden mini-series.
Summary[]
As the mysterious man guides the weapons towards Sasuke, the latter easily deflects them with his sword before pointing it against the opponent, who catches it in order to let his son land a successful attack. However, Sasuke's Rinnegan lets him swap places with Shin, shooting a dense ball of fire to complete the counter-attack. The attack is deflected thanks to the enemy using Shin as a shield, though both of them get caught in the explosion. Noticing Sasuke's great ocular prowess, the enemy presents himself as Shin Uchiha, to which Sarada comments that he has the same name as his son. After telling Naruto to take care of the children, Sasuke goes on the offensive, but adult-Shin manipulates the opponent's sword into stabbing Naruto, who ends up deactivating his chakra cloak due to the injury. Since the cloak had blocked some weapons beforehand, the sudden lack of protection led Sasuke to shield his daughter with his own body, which ends up being paralysed by said weapons. Sakura arrives in time to stop the two enemies, punching the older Shin into the ground. However, as Sakura apologises to Sarada for the situation, Shin's creature teleports both Shins – along with Sakura, who got caught up in the technique – to their base, where the father orders her to transplant his injured son's organs into his own body to repair the damage she had caused.