On Teen Wolf Season 6 Episode 20, Stiles and Derek show up to the shipyard and help take out the hunters. Monroe flees.
After handling the hunters and listening to Deucalion's final words, Gerard comes over the radio in Roscoe, telling Scott where are his friends are. Jackson, for instance, is in the tunnels by Gerard's armory. Scott tells Theo to go to the hospital to buy some time.
Scott, Malia, Lydia, Stiles, and Derek reconvene at Deacon's clinic to come up with a strategy and to catch Derek and Stiles up on what's been happening. The plan is to divide and conquer. Lydia and Stiles go and rescue Jackson and Ethan, meanwhile Scott, Malia, and Lydia head to the high school to lure the anuke-ite there.
At the hospital, Melissa saves Nolan, and they save Liam and Theo from hunters. Meanwhile, Noah Stilinski saves Parrish from some deputies who had him trapped in Eichen, in Halwyn's old cell. From there, Noah and Parrish save Rafael and begin unarming the residents of Beacon Hills.
Monroe shows up at the school and shoots Scott with a yellow wolfsbane bullet, but Derek is able to save Scott by burning the wolfsbane out of him. Scott figures out how to trap the anuke-ite, and he calls Stiles and tells him to grab something from Gerard's vault.
The anuke-ite manages to turn Peter, Malia, Jackson, Ethan, and Derek to stone before going into the library to battle Scott. As an attempt to get Scott to open his eyes, the anuke-ite takes the form of void!Stiles, the nogitsune, and some other previous villains.
Scott doesn't open his eyes, and he blinds himself with his claws to make sure the anuke-ite can't beat him. Then, Stiles arrives and throws mountain ash on the anuke-ite, trapping it forever.
This allows everyone to break out of stone. With help (aka a kiss) from Malia, Scott is able to heal and restore his eyes.
In the armory, Kate and Argent tell Gerard that Scott has won, and it's all his fault. After shooting Kate with a yellow wolfsbane bullet, Kate attacks Gerard and presumably kills him.
Sometime in the future, Scott and Argent rescue a young werewolf, Alec, from hunters in some big city. Scott tells him the story of this war and then asks if he will join the fight. It turns out Monroe is still leading thousands of hunters all over the globe, and she attacked Alec.
Scott tells Alec that he can join Scott's pack, only if he is willing to fight. Liam, Stiles, Derek, Malia, and Lydia show up to help Scott take on this next with with, presumably, Monroe, and Alec joins up.