This is a better script for Game of Thrones season8 episode 3 could have been written:
First: backstory, They create a believable backstory for the Night Kings, and explain his creation and why he wanted to kill the three-eyed raven. Because if he was created by the children of the forest to wipe out humanity and he’s not happy about his own creation so unhappy that he creates all the spirals with the dead as blasphemy against his creators, why then he keeps pursuing the goal of getting rid of humanity?
Second: a battle plan:
The most important part of the battle plan should be to avoid losses in your army because every soldier you lost is a soldier for the enemy! So definitely no blind charge of the Dothraki! You have a castle, so you fortify the castle and wait for the enemy to come into your ground, the ground that you have prepared for them, maybe flammable ground that you can light from afar. Trenches, with dragon glass spears, all along the way to the castle, archers many many archers, the scorpion with dragon glass to kill the undead Viseryon, trebuchet to keep them away not used one time and then abandoned.
Wait for them, destroy them with the unsullied and flank them with chivalry.
Give the Dothraki dragon glass, why they didn’t have dragon glass? Why there wasn’t any fire to light the outside field of Winterfell?
Keep the dragons on top of the castle to protect it from the undead dragon.
Keep Ghost in the Goodwood to protect Bran Stark. The walls should have been manned since the beginning, with archers all the way, and things to throw down at the dead to repel them.
Melisandra shows up with a bunch of priest and priestess and they light a huge fire around the castle and they lead our heroes to the right place with the right hints like Melisandra did.
Bran could gather hundreds of ravens to make the NK fall of his dragon, when the NK is distracted Dany could easily burn thousands of dead, while Jon engage the NK in an epic one on one, but undead Viseryon get rid of the Ravens and attacks Jon, Jon fights undead Viseryon, and the NK walks away Meanwhile all the other characters fight the dead some fall, saving others. The dead are too many, and even if the defense is strong a fall back is called, the unsullied cover the fall back with heroic power like the Spartans at the Thermopolis.
The castle is about to fall and the dead are breaking in.
Arya is fighting on the wall, sees Jon fighting Viseryon and she jumps on top of the undead dragon stabbing it with her Valerian steel dagger. Jon and Arya stark run to the Goodwood killing zombies along the way. Jon snow sees Sam and stops to save him, Arya keeps going, Jon saves Sam and sends him in the crypts. The Night King is about to enter the Goodwood when he raises his hands to revive other dead. In the crypts, there are many more people than what they showed us, and the dead start to get out of their tombs, zombie Rickon, zombie Ned with no head, etc… Sam and Tyrion and some other soldiers let in the crypts fight the dead, Sansa uses the dragon glass to stop zombie Rickon. Missandei dies because of Varys cowardice.
The dead rise: Jon is surrounded, but Rheagal shows up and burns them all.
Meanwhile, the generals of the Night King enters the castle and they engage battles with Brienne, Jamie, and Jorah. Dany lands Dragon to try and help Jorah, but dragon fire has no effect on the NK’s generals, the dead attacks Dragon and Dany fall from him, Brienne kills his general and run to the rescue of Dany, they are surrounded by dead and they are about to die when Jorah kills his general and run to their rescue, he brings Dany away from the scene. Jamie is still fighting with the last general while Brienne is killing dead like a demon, she reaches to help Jamie. Dany and Jorah keep killing dead but Jorah dies as in the show. Dragon comes to her rescue.
Bran wargs into Nimeria and bring a pack of hundreds of wolves into the castle, to fight for the living. Meanwhile, Theon’s iron born are decimated by the dead, and Ghost is mauling dead one after another. The NightKing enters the Goodwood, Theon and the iron born fight him valiantly but all die. The ghost throws himself at the NK but it gets stabbed. Dany is furious for Jorah’s death and reaches for the goods wood, she tries to burn the NK but he suffers no injury and sends a javelin into Dragon’s chest straight from the flames. Dany falls with Dragon.
Jamie is overwhelmed, hurt and tired, he and Brienne are surrounded by dead and the general is still fighting. Brienne gets badly injured by the general, but she managed to kill him with her last strength before she collapses. Arya arrives at the goods wood and engages a sword fight with the NK who is too strong for her, she struggles evidently but she keeps going.
Jon arrives with Reaghal dismounts and sends him to fly as he sees Dragon on the ground. Nimeria enters the goods wood and sniffs his dead brother while Jon approaches the NK with Long Claw in his hands, dramatic music, the remaining dead are mauled by random wolves, Nimeria go to Arya’s rescue and so does Jon, the NK is overwhelmed Jon snow keeps hitting him with all his strength meanwhile the dire wolves are dragging him side to side, but he keeps defending himself. The NK is not like his generals he does not die with a slash of Valyrian steel. So even though Jon keeps slashing him he doesn’t die. Arya throws herself at him with wild animal violence and stubs him in the chest with her valyrian steel dagger and he disappears. All the undead fall dead again and Jamie picks up Brienne in his arms, crying, and says to her “we won the great war!” She dies.