Yeah, Book 3 is turning out to be quite amazing. Really happy with those three episodes.
[spoiler]Folks on another forum pointed out how the new villains have been imprisoned for 13 years. Or since Korra was 4, which is when she discovered she was the Avatar.
Odds are they tried to take her out, hence the ridiculously high-security. This also explains why everyone was so overprotective of Korra; that compound was built to keep her safe in case the villains tried to take her out again.
Remember Zuko's first instinct was to alert Lin because they'd be after the Avatar. So odds are that quite a few people were in on the protection plot for Korra. Tenzin was also supposed to move to the South Pole to teach Korra Airbending there, so he was likely in on it too.
It's actually kinda ironic that Korra leaving the spirit portals open has now allowed for those who likely tried to take her out once to try again with greater power.
Oh and also OLD ZUKO IS JUST AS AWKWARD AS EVER
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