A year after the conclusion of the Hundred Year War, Toph found Ho Tun in a ramen house raving over having swallowed half of a spider wasp in his soup; his over-emotional state inadvertently causing Toph's bracelet to vibrate slightly. Ho Tun then enrolled into the Beifong Metalbending Academy near Yu Dao along with two other earthbenders who had similarly affected the bracelet in order to begin learning metalbending. However, Ho Tun's improvement was slow, as he had yet to move a single coin when Sokka visited the academy.
When a rival firebending school under the leadership of Master Kunyo forced them out of the school, Sokka bought him and the other students three days during which they could prepare for a "match to the sit", a battle in which the first team to force someone on the opposite team to sit down would win the rights to use the building. After several unsuccessful attempts to metalbend, Ho Tun and the rest of his classmates decided to leave in order to avoid "doom". However, as they were heading out, they overheard Toph saying to Sokka that she had expected them to become metalbenders, but that it was unjust of her to force them to become something that they were clearly not. Moved by her statement that she expected them to be something, Ho Tun and his friends discovered the secret of metalbending.
The next day, when Toph was about to sit down in defeat before Master Kunyo and his firebending students, Ho Tun halted her by metalbending a coin to her behind. He, The Dark One, and Penga proceeded by effectively defeating the firebending students and their master by metalbending several coins at them. Ho Tun thanked Toph for believing in him, as, although she never said a kind word about him, he admitted that she was the first one who expected him to be something more than a "wimp". In the fight for the Harmony Restoration Movement, he, Penga, and The Dark One helped Toph when she was in trouble by metalbending the Fire Nation soldiers' helmets.
Gene Yang was originally going to have Ho Tun constantly obsessing over death, but the idea was deemed inappropriate by Nickelodeon for the target age group. Therefore, Gene replaced it with an obsession with "doom", leading to what he feels to be a more comic effect.
Ho Tun was the first student to learn metalbending, and thus became the second person, in addition to being the first male, in history to ever bend metal.
Upon figuring out how to metalbend, Ho Tun became Penga's new crush, much to his surprise.