Someone got their book 15 days early. Spoilers are in this thread on reddit. I will be updating the OP and post them here.
https://old.reddit.com/r/wow/comment...orm_early_ama/
Disclaimers:
The Burning of Teldrassil is not featured in this book.
* Symbol means IMPLIED.
Minor Spoilers:
Forsaken:
A few of the Forsaken during the meeting wish to defect to the Alliance.
Turalyon, Genn, and Faol:
Turalyon and Faol see eachother again. Turalyon almost kills Faol upon the moment he looks at him. He calls him a disgrace and shouldn't be. After touching Faol he feels the Light inside the Undead and falls to his knees crying before apologizing to his old mentor. The three are brought to the meeting to understand the idea of the gathering that the Forsaken can be reasonable people.
Windrunner Reunion:
While not featured in the book it is mentioned that it didn't go well and only how each sister had changed over the years.
Magni, Moira, Anduin, and Dagran.
Magni tells them that Azeroth needs to be healed and all. Before leaving Moira asks her father to see Dagran, his Grandson. Anduin has funny moments with the child.
Tyrande:
Tyrande discusses Cenarion Hold and the situation in Silithus with Anduin at Teldrassil.
Major Spoilers:
Anduin:
After being crushed by the Divine Bell, Anduin can tell if someone is lying or not. [Basically Light Spidey-Sense] He also cannot make any wrong decisions without feeling physical pain.
Anduin had rebuked Genn and Rogers for their actions in Stormheim for taking the situation too far than it should had towards Sylvanas and the rest of the Horde.
Anduin doesn't want to marry Tess to keep future Wrynn-reign over Stormwind. Anduin wants to marry out of love.
Anduin sneaks Calia into the meeting after hearing her sad story which basically breaks his own rules of the meeting.
While he and Faol holds Calia's hand, he can feel an "ocean of Light" within her as she is revived by the Naaru at Netherlight Temple. After learning of what happened at Arathi, Anduin says Sylvanas is a person who will never ever truly change.
Sylvanas:
When Sylvanas was asked directly by Anduin did she betray his father she has a flashback of Vol'jin telling her to save the Horde. She tells him Varian's fate was set in stone due to the Legion's countless numbers. During the meeting in Arathi Highlands, Alonus Faol asks if anyone wishes leave, do so now. Some humans leaves and Sylvanas rubs it in his face that they'll never truly accept "us". When Sylvanas sees the defecting Forsaken heading towards Stromgarde to defect after discovering Calia is still alive, Sylvanas blows her horn, meaning the Forsaken need to return to their side of the field, they decided to not to and she began to shoot down the defectors. Calia tries to run but Sylvanas shoots her dead.
Calia Menethil:
Calia lost her husband and child during the Blight in Lordaeron. She stayed two days lying in a ditch until Faol found and rescued her. She thought she would find her husband and daughter in the Undercity which is a reason why she decides to attend the meeting. She tells Anduin a sob story which allows her to get snuck inside the meeting by him. Calia attends the meeting disguised under a hood. After she had revealed herself a Forsaken recognized her and told her "it's time.". This caused Forsaken defectors to head towards Stromgarde to leave and rejoin the Alliance. She had a choice: Support them and get them to safety or let them die after Sylvanas catches on. Calia runs from Sylvanas but Sylvanas is too agile and kills her with a shot of her bow to defend her claim on Lordaeron.
Baine:
Baine was having secret communications with Anduin until stopped by Sylvanas. He was also lied to by her after asking what were the Goblins doing in Silithus and she said they were merely investigating. He wanted to rebuild Cenarion Hold. He's passive aggressive to Sylvanas. Baine sends Anduin a piece of his horn and a farewell letter to him via Valeera.
Old Gods:
There are no Old Gods in this book.
Mod Edit: I removed information proven false from the Reddit article's OP, you can amend the post later if you like.