The Legend of Korra, Book 3: Change

White Lotus Sentry:
They came out of nowhere. I'm so sorry, Lord Zuko.

Zuko:
How could you let this happen?

White Lotus Sentry:
They caught us by surprise. And Zaheer is an airbender now.

Zuko:
No! This can't be. Do you have any idea the power these criminals possess? Individually, they can take down any bender. Put them all together, they could take down the entire world. And now you're telling me their leader is an airbender?

White Lotus Sentry:
We can track them...

Zuko:
We don't need to track them. I know exactly where they're going. Notify the new chiefs of the Northern Water Tribe that an attack on their prison is imminent. And send word to Lin Beifong in Republic City. The Avatar must be protected.

White Lotus Sentry:
Where are you going?

Zuko:
To stop them.