Episodes 1 & 2
The main storylines:
#1. How will the north react to Dany's arrival
#2. Arya reaction to all her reunion
#3. Will Jon accept a mariage pact with a Northern lord
#4. Will Dany's pregnancy affect that pact
#5. How will Sam take the News that Dany murdered his Father and Brother
#6. What Flash backs will Bran have
#7. Will Melisandre get back to WF, as Old Lady Mel
#8. Will Theon find Yara alive
#9. Will Tormund and Beric make it to Winterfell
#10. What will Jon's reaction be when he finds out about his real parents
This is how i think it goes, their will be 3 battles in season 8, two at Winterfell and the main battle in Kings Landing.
Battle of Winterfell
A plague sweeps through Winterfell, causing many unsullied and dothraki to die. Of Course when the AOTD arrive all unsullied and dothraki turn into wights. They rise up and attack winterfell, weakening them the city for the larger army of dead soldiers to attack. Reinforcements come when Ed, Tormund and Beric arrive with the freefolk and night watchmen. But the living are almost defeated, until Melisandre uses her magic to fight Night King. Mel forces NK to retreat south. This Battle will probably cover 2 episodes. The most notable event of the battle, is the death of Jaime Lannister. Jaime, saves Brienne from a White Walker, He ends up dying in Brienne's arms. This event will cause Tyrion to side with his sister and betray Jon and Dany. It is also the battle where Rhaegal dies
Forging of Lightbringer
Jon loses Longclaw during the battle. When Jon stabs Night King and longclaw shatters into thousand pieces. With help from Mel and Sam, Jon discovers the secret to lightbringer. Jon, Sam, Gendry and Melisandre with Drogon travel to Dragonstone. There, Gendry forges Lightbringer with dragonglass, dragon fire and Jon's Targaryen blood.
Sack of Winterfell
Driven by Grief, the death of Jaime was to much to handle. Also the realization he must now protect Cersei's unborn child. Tyrion helps The Golden Company sack Winterfell. The first major death in the sack is Sansa Stark. I predict that she will die trying to save someone(Arya or Dany) from a burning building only to get trapped and die. The second major death is Bran, I think he burns at the wierwood tree, when a GC Soldier sets him and the tree on fire, This has a effect on Night King. He was born at a weirwood tree. His magic like Bran's green seeing magic comes the weirwood. Tyrion also takes Dany hostage. Theon takes the survivors to Dragonstone. Where Jon must face the harsh reality of Tyrion's betrayal.
Cersei and Euron
It is my belief that Euron, sometime in season 8 causes Cersei to miscarry. When Tyrion arrives back to KL with Dany. Tyrion will be furious about the miscarriage, seeing that he based his decision to betray Jon and Dany on protecting Cersei's unborn child. In turn when she finds out about Jaime's Death, it will turn her into the mad queen. She throws Tyrion into the black cells with Dany.
The Black Wedding
The Mad Queen and Euron get married in the Dragonpit. The wedding gets crashed by the NK and Viserion.
Battle of King Landing
AOTD storm the gates of KL. The Golden Company fight AOTD.
AOTD begin to enter The Red Keep
Back at the dragonpit, Jon Snow has arrived on Drogon. Him and NK have a Dance of Dragons style battle. The dual ends up back at the dragonpit, Jon kills NK with lightbringer and Drogon kills Viserion with Drogon surviving.
With NK defeated, The Hound and Brienne attempt to rescue Dany. The Hound wins cleganebowl. Brienne kills Harry Strickland and rescues Dany. Brienne however leaves Tyrion in the black cells.
Jon is attacked by Euron in the dragonpit, but he is saved by Theon. He kills Euron and avenges his sister.
A crazed Mad Queen prepares to leave KL with Qyburn. Jaime appears out of nowhere and kills Qyburn. Jaime tells Cersei, "It should just be the 2 of us". Cersei embraces and kisses Jaime. But Cersei notices Jaime has two whole hands. She tries to pull away, but Arya takes Jaime's face and murders Cersei.
Aftermath
King Aegon and Queen Daenerys reign over Westeros. They have a Son. Arya and Gendry retired to storms end. The Hound and Brienne become Kingsguard. Tyrion is executed for his crimes. Theon becomes King of Iron Isles.
The series ends with Sam reading from Ebroses history book, A Song Of Ice & Fire