13. Venom of the Red Lotus

Complete story — includes the ending

The Red Lotus tortures a chained Korra by poisoning her with mercury, in order to force her to the point of death, triggering the Avatar State before they kill her, which would end the cycle of the Avatar's rebirth. However, a wrathful Korra overpowers her captors and fights Zaheer in the skies. Meanwhile, her friends find and rescue the airbenders. After Mako electrocutes Ming-Hua, he and Bolin narrowly escape Ghazan's collapsing the Red Lotus's lair on top of himself. As Korra is about to succumb to the poison, Jinora leads the airbenders to pull Zaheer out of the sky with a massive air vortex formed from their combined bending. Zaheer is captured, and Suyin metalbends the poison out of Korra. Two weeks later, in Republic City, a weakened Korra, using a wheelchair, watches as Tenzin anoints Jinora as an airbending master and rededicates the Air Nomads to a nomadic life of service to the world, following Korra's example.