As Voldemort's Horcrux, Nagini remained by Voldemort's side almost every moment, under his protection.
Only for a few hours each week did Voldemort permit Nagini to leave Avery Manor and hunt in the nearby primeval forest, granting it a small measure of freedom. That was also Voldemort's favoritism toward Nagini.
After all, even the Death Eaters at Avery Manor were forbidden from leaving before Voldemort led them in an assault on Hogwarts Castle. They were forced to practice methods of plundering the power of the stars, preparing for war.
Fortunately, aside from Hufflepuff's Cup, Linley and Irina had destroyed Voldemort's other Horcruxes in secret. Voldemort did not know that, apart from Nagini and Harry Potter—whose status as a Horcrux even Voldemort himself did not know about—all of his Horcruxes had already been destroyed.
Voldemort still naively believed that Hufflepuff's Cup was the only Horcrux that had been discovered.
Otherwise, Voldemort would never have allowed Nagini to leave Avery Manor, giving Linley an opportunity to exploit.
A week after Harry obtained the memory from Slughorn, Linley captured Nagini in a primeval forest fifteen kilometers from Avery Manor. After temporarily restraining it with the Full Body Bind, he used Apparition to bring it to the Forbidden Forest at Hogwarts.
In truth, if Linley had been willing to conduct a carpet search, he might have been able to locate Avery Manor by finding Nagini and following the trail. After all, Avery Manor was not protected by the Fidelius Charm.
But that would have taken far too much time. Besides, before all the Horcruxes were destroyed, he could not truly kill Voldemort. There was no need for him to do that.
"Irina, go call Neville over."
Linley landed on the ground. After casting several more Full Body Binds on Nagini lying immobile on the