Unbraceable You is the first episode of season 6.
Sue's senior year, the "Year of Sue," begins with the premature removal of her braces. Meanwhile, Axl finally beats Mike in basketball, and Brick tries to find the perfect backpack for school.
The Hecks spend their last Friday of their 'perfect summer' lounging in the pool, only to find out that school had started Monday earlier that week.
After Sue and Brick try to make the last part of the school day, Axl and Mike play 1-one-1 basketball. Axl actually beats Mike, much to both of their surprise, as Mike never lets his kids win at anything. Mike responds by saying that if you put a monkey at a typewriter, it will eventually type a sentence. After a second game, Axl beats Mike again, much to Mike's chagrin.
Sue and Brick return home from school after being there for only 47 minutes. Sue is distraught that she missed out on the first week of her senior year, dubbed the "Year of Sue". To worsen her situation, the only other person in her class that had braces got her braces off over the summer, leaving Sue as the only senior with braces still on.
After Brick notices that everyone else in his class is getting more mature, he decides that he needs to move on from his Shaquille O'Neal backpack and get a new one. He goes through many ideas, such as a messenger bag, guitar case, and the baby front carrier that Frankie used to carry the Fergusons' Baby in.
Sue goes to the orthodontist, and even after 8 years of having braces and her teeth looking perfectly straight, Dr. Niller still says, "See you in 3 months" due to her bones being spongy. Frankie stops him and demands that he take the braces off. They return home, and Sue shows off her new straight teeth, which leave Axl without insults.
Mike plays Axl again in basketball and loses again. Afterward, Axl tells Brick that he noticed Mike was slowing down lately and that he doesn't feel so good about beating him anymore. Brick explains that it's the natural order of things, that adults are supposed to slow down, and that Axl and Sue will replace Mike and Frankie.
Sue looks at her "straight" teeth in the mirror, only to find that they are rapidly shifting all over the place again. She becomes extremely upset and thinks that this is the Universe's way of telling her that she should stop trying and give up.
Mike and Axl play Bill Norwood and his nephew, AJ, in a game of 2-on-2, and win, which causes them to realize that adults may slow down, but they can still hitch a ride on their kids until they stop completely.
Sue returns to the orthodontist, and Dr. Niller tells her that he can fix the shifting completely without putting braces back on at all. Sue proceeds to wear a retainer for a year and wins her sought-after school office of Sergeant-At-Arms.
Brick finally solves his backpack dilemma with a miracle from a dumpster: a pizza warmer bag.