Lord Fourth Lives: A Naruto AU: Minato's Mistake: Orochimaru's Over-step and Uchiha Unrest by EnviousWorm
Unable to mourn for long, Minato assembles his council on the word of his sensei - the Sannin Jiraiya - who claims to have news about his friend and ally, Orochimaru.
On the night of October 10th, the Nine-Tailed Fox attacked the shinobi village of Konohagakure. In many versions of this story, Namikaze Minato - the Fourth Hokage - gives his life for the village, sealing the Nine-Tails in his infant son, Naruto, born that night. But what if Minato survived? And, in his place, his son Nartuo and the old Third Hokage, Sarutobi Hiruzen, die instead -- alongside his wife, Kushina? Now the young Minato must navigate a dangerous situation, rebuilding Konoha and dealing with the potentially rebellious Uchiha clan. All while handling a massive amount of grief.