Hail to the Teeth

"Hail to the Teeth" is the 11th episode of season 31. It aired on January 5, 2020.

Plot
Lisa is walking down the sidewalk of a street reading Li'l Eco-Warrior Magazine, when she meets a man that tells her she'd be more pretty if she smiled.

At dinner, Lisa tells the family about it, and Bart shows her with an app, Puber, how she'd look in puberty, with a picture of her with braces. Marge explains that the orthodontist they originally went to (Last Exit to Springfield) was a rouge periodontist and Lisa has to get braces again due to playing the saxophone. Afterward, Marge brings a gift they received to the table, a hologram of Artie Ziff inviting them to his marriage.

At Kidzrule Orthodontics!, Lisa gets the braces to her upper teeth and can't stop smiling broadly due to them.

At Artie's bachelor party, Homer and Marge listen to how Artie met the new woman of his life. Kent Brockman fails to get the attention of the wedding planner (even though he's married). Homer gets into a food coma after eating a pig.

At school, everybody compliments Lisa, having changed their look on her thanks to the smile.

At the wedding, no-one is sitting on the bride's side. Homer is asked to walk the bride down the aisle, and after negotiating to get an extra piece of cake, agrees. After Artie and his bride exchange their own vows, the Rabbi pronounces them husband and wife, and Artie removes her veil to reveal that his bride looks exactly like Marge.

Lisa finds herself with new power, to influence people to do good, and starts using it at school for recycling and stopping the bullies, so she candidates as student body president. With 1 week to go to the election, she returns to Kidzrule Orthodontics! to get the braces on her lower teeth and loses her smile, turning it into a permanent frown. The doctor says it will be like that for six months. Meanwhile, Wiggum, Eddie and Lou go in search of Ralph's retainer on Garbage Island, after he finds out that a new one would cost $500.

Later, in the hotel, while Homer is taking everything out of the mini-fridge, Marge and Homer find out from Artie that his wife is really a robot and that he built many robots in her image. Marge convinces him he can use them for good, and they build the Orfanato de Artie Ziff, an orphanage. When he tells an interviewer his future will be marrying one of them, they all fly away.

At the Student Council debate, Mary Bailey is the moderator, and introduces Dubya Spuckler in person, and Lisa on a Skype call due to her being "sick". Her trick to hide the frown fails when Martin fails to use the program to modify her image properly. Everyone sees Lisa's frown and they all lose confidence in her, voting for Dubya. Marge manages to console her, but it is revealed that it was one of Artie's clones. Later, Artie is at dinner with 5 other clones and they prefer to power down than to continue to have dinner with him.

During the closing credits, several moments of Lisa growing up with a frown on her face are then shown, with the last image being her with a happy face, meditating under a tree.

Promo videos

 * Twitter - logo.png "Hope you're hungry — we're serving up extra helpings of laughs TONIGHT at 8/7c! 🍽" on Twitter
 * Twitter - logo.png "Hope you're hungry — we're serving up extra helpings of laughs TONIGHT at 8/7c! 🍽" on Twitter
 * Twitter - logo.png "Hope you're hungry — we're serving up extra helpings of laughs TONIGHT at 8/7c! 🍽" on Twitter