Fleshed out a bit....
Episode 12: The End of Diplomacy/ Breath Before the Storm/ The Last Debate
Frame: A member of the White Council (Círdan?) arrives in Rivendell. Clearly, Gandalf's visit has set something in motion. Elrond is involved, but just how involved he and the elves of Rivendell will be remains to be seen. Elrond goes to Gilraen's cottage to give the lesson, to escape from the main house at Rivendell for awhile.
1.
In the Forests of Middle Earth: Yavanna encounters a 'wild' (rabid) beast (dinosaur, giant sloth, other?) that attempts to attack her, but she just puts it to sleep. Yavanna then comes across Oromë and asks if he has been hunting 'her' creatures. He points out that this creature is dangerous and no longer how she intended, so perhaps killing it would be best. He also says they would be a hazard to the Children, whom he is looking for.
2.
Aulë's Forge: Yavanna talks to Aulë about her concerns for her creatures. He confesses to her about the dwarves. She says, 'You should have talked to me.' She is clearly upset with him for doing this without her knowledge, and leaves. He continues working on a chain he has been forging (slowly, since episode 8 - it was visible in his workshop during the Ossë incident). Mairon asks him what it is for, since he's been spending so much time on it lately. He explains that this chain will 'lock' a Valar/Maiar in their form, to prevent them from escaping, and makes it clear that he intends to use it on Melkor 'if necessary'. Horrified, Mairon tries to defend Melkor, and explain that it's all been a terrible misunderstanding, but that they could still reconcile with him. Aulë will hear none of it. Mairon steals one of the links of the chain, and leaves.
3.
The Ring of Doom: [Mandos mentions the awakening of the Children?] Yavanna talks to Manwë about Ents and Eagles (not giving away Aulë's dwarf secret). Manwë does not seem convinced. The other Valar gather together to determine what to do about Middle Earth. Manwë wants peace - others are in favor of fighting or passively going along with someone else. Manwë asks Mandos to speak, and he says, "I'm not the one you should be asking." Manwë decides to send Eonwë to summon Melkor to their council, so he can speak for himself and settle this once and for all.
4.
Utumno: Mairon gives link to Melkor, and explains what Aulë intends. Melkor paints himself as someone about to be besieged. Eonwë arrives, and Melkor sends Mairon out the back door to keep his association secret (for his own safety, of course...) Melkor gives Mairon the idea to revisit the ruins of Almaren. Melkor politely declines Eonwë's summons (okay, more with a sneer, but he's not violent). He then sics Gothmog on Eonwë, who is chased/captured/imprisoned by all the balrogs with that link.
5.
Taniquetal: Manwë and Varda talk; he decides to consult Ilúvatar, she decides to make the stars.
Massive Montage!
Manwë's vision on the peak of Taniquetal of the Music and the future of Middle Earth, with a (remembered) line from Ilúvatar about everything becoming part of his theme. The vision shows him images from the future (the Fall of Gondolin, orcs?) and Manwë realizes what Melkor intends to do with the Children.
Varda kindles the stars using the Light of the Trees.
Melkor in Utumno prepares for war.
Mairon, wandering in Middle Earth, sees the newly kindled Sickle of the Valar and then later hears singing (offscreen).
6.
Taniquetal: Manwë comes down from the peak of Taniquetal and tells Varda he knows what he must do. The eagles are with him now.
7.
Utumno: Melkor's preparations for war involve getting rid of the messenger. The balrogs kill Eonwë, throwing his body down a cliff. We see his broken body on the ground and his spirit flees back to Valinor. Manwë sees what Melkor has done, and Eonwë goes to Lorien for healing/rebirth. Mairon returns to Utumno, and when Melkor asks him, 'Well, are you with me or with them?' Mairon replies, "I've found the Children, my lord."
Frame: Gilraen confronts Elrond over whatever he is hiding from, offering her advice: the worst decision is to not make a decision.