Frame stories thus far:
- Season 1: TA 2941 Gilraen 10 year old Estel is being raised in Rivendell by his mother, and tutored by Elrond concerning the earliest history of the world. Thorin and company pass through Rivendell on their way to the Lonely Mountain.
- Season 2: Arwen in Lothlorien contemplates her place in the world and the role of the Evenstar - does she belong in Middle-earth or Valinor?
- Season 3: TA 2947 Teenage Estel sneaks out of Rivendell for adventures with the Dúnedain. He befriends Hamilcar, who dies for him.
- Season 4: TA 2949 Balin, Gandalf, and Bilbo return to Erebor for an anniversary of the death of Smaug.
- Season 5: Gandalf's adventures in Harad as the return of Sauron impacts the area.
- Season 6: TA 2952 Arwen returns to Rivendell, concerned that the elves must flee before hope is lost. She meets 20-year-old Estel, who falls in love with her. He decides to go out into the Wild (after learning his name and heritage).
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We will need six more frame stories to take us to the end of the First Age in the main story. Probably 3 of those will be Aragorn-centric. We have three Thorongil frame stories available: his time in Rohan, in the court in Gondor, and his adventures in the East/South. We would have to decide which season each of those fit best with, and if we want to do more than one frame in any of these settings.
So that would leave three 'other' frame stories, focused on different characters. We can focus on characters we've already introduced (such as Elrond, Galadriel, Gandalf, or the Sons of Elrond), or we could come up with new stories/characters to introduce.
Other events to work with:
TA 2951 - Nazgûl reoccupy Dol Guldor
TA 2953 - Last Meeting of the White Council
TA 2954 - Mount Doom reawakens
TA 2956 - Gandalf and Aragorn meet
TA 2980 - Betrothal of Aragorn and Arwen (save for a 2nd Age Frame, probably)
The Thorongil adventures occur during the 2956-2980 timeframe. So it might be nice to have one frame before we get into that story, though Aragorn could still appear as a cameo as he is now on adventures out in the world.
If Season 7 is going to be about unity/alliance/seize the day, then it could be a good fit for Aragorn in Rohan. He will be establishing himself for the first time as Thorongil. While he feels it is his purpose to go out into the world and do this...he's going to need allies, and he has a lot to learn. That could also possibly work with Season 8, as we'll have Túrin in the courts of Doriath and Nargothrond.
Likewise, either Season 11 or 12 could be a good match for Aragorn journeying off into the unknown to confront the evils of Sauron more directly. Our Harad prince from the Season 5 frane (who has been in Gondor's court ever since) could accompany him.
I think that Season 10 (the fall of Gondolin) will be a good time for Thorongil to make it to Gondor