Zuko is telling his grandchildren the story of how he and Katara fell in love.
Zuko: It was love at first sight.
Katara: You called me a peasant.
Zuko: I saved her from the pirates.
Zuko: I wrote her a romantic haiku about how she rises with the moon and I rise with the sun, and told it to her at dawn in a spirit oasis.
Katara: You blasted me into a tree!
Zuko: We had a date in a cavern lightened by crystals.
Katara: We were prisoners of Dai Li.
Zuko: Then we were separated for a while. I always thought it was because she had a problematic relationship with her emotion...
Zuko: When we reunited she visited me at night.
Zuko: A while after that we hugged at sunset.
Zuko: Of course, my sister had some troubles accepting her.
Zuko: In the end I had to take a lightning for her.
Katara: At least you got something right.