Luan flosses too much and her teeth fall out.
The episode opens in Luan and Luna's room at night. The two siblings are inside, donning their pajamas. Luan is telling jokes from a cardboard stage. She finishes a joke and Luna applauds her.
Suddenly, Rita calls to the two sisters, asking if they're ready for bed, as, according to her, they had stayed up a little later. Luan realizes that she hasn't flossed and Luna has not put on her facial scrub. They go to the bathroom to finish their nightly routines.
Luna puts on her scrub as Luan pulls a long strand of mint floss off of the container. She laces it in the small gap between her teeth and begins to floss. Luna comments that her sister overdoes her flossing. Luan reminds her that the dentist suggests that she should floss after every meal. The older sister tells her that a snack does not count as a meal. Luan ignores this, a quality that is unlike her. Suddenly, two objects fall into the sink. After scooping them up, Luan realizes that the objects are her two front teeth. This causes the two sisters to panic, as the teeth were not meant to come out. They rush downstairs, the younger in pain.
Luna explains what happened and Rita nods in understanding. She says that they'll visit the dentist in the morning. The siblings return to their bunk bed, where Luan lays silently.
Luna, concerned about this odd silence, asks her sister what is wrong. Luan replies agitatedly that it's her mouth before feeling a sharp amount of pain. She turns on her side in bed, ignoring her sister for the rest of the night.
A transition to the next day shows Luna in the van next to Luan, who looks agitated as she wears a cast for her mouth. Luna talks to Luan about why she's been so quiet. She assumes that it is the pain of the missing teeth. Luan nods no as she pulls out some paper and writes on it. It says "I'm scared that my mouth won't get better. What if I can't tell jokes after this?" along with a frowny face.
Luna reminds her that she is Luan Loud and that she will find a way to make people laugh, even if she suffers from intense mouth pain when she talks. To cheer Luan up, Luna tells a tooth related joke. Luan musters a slight laugh, as she can not laugh harder due to her pain.
While at the dentist, Luna reads a joke book in the waiting room and thinks about her sister. She hopes that she'll be okay after her surgical procedure.
Suddenly, the door opens, revealing Luan, Rita, and the dentist. Luna gets up to approach her sister. Luan explains that, to keep her surgically reattached teeth in place, the dentist decided to go through with her already planned orthodontal procedure of putting on her braces. She smiles to show her sister her brand new blue braces and asks what she thinks.
Luna replies that she is at a "floss for words", along with Luan, who suspected the upcoming pun. The sisters laugh as the episode ends.