Book 2 Chapter 12 "THE SERPENT'S PATH"

After leaving the desert, the group fortuitously meets Suki and attempts to lead a pregnant woman and her husband through the Serpent's Pass, a dangerous route to the outlands of Ba Sing Se. They are attacked by a Fire Nation ship and narrowly escape. Suki and Sokka attempt to rekindle their relationship, but Sokka his hesitant due to being unable protect Yue. Meanwhile, Zuko and Iroh, assuming new identities as Earth Kingdom refugees, are also on their way to start a new life in the Earth Kingdom capital, and encounter Jet and some of the Freedom Fighters, with whom Zuko starts to bond. Aang and the group are attacked again, this time by the route's namesake serpent. He and Katara defeat the beast and the group arrives on the outskirts of Ba Sing Se. There, Ying goes into labor and delivers her daughter. Sokka and Suki share their first kiss, while Aang confesses to Katara how the happiness of Ying's family reminds him how he feels about Appa and her. Aang departs with Momo to find Appa in Ba Sing Se, but is shocked to see that a massive Fire Nation drill is approaching the wall of Ba Sing Se.