'America's Got Talent' Quarterfinals: Blind, Autistic Singer Makes Everyone Cry With Amazing Piano Performance

Kodi Lee is every bit as amazing as we remember.

After an emotional pre-taped package -- which follows Kodi's mom as she explains how she found out her son was blind and autistic and how she connected with him through music -- Kodi hits the stage and delivers the kind of performance that AGT was made for.

Sitting at a piano and using nothing but his prodigious talent, Kodi performs a rendition of Simon and Garfunkel's "Bridge Over Troubled Waters" that brings everyone in the theater to tears.

The judges can hardly keep it together as they give Kodi feedback, and Simon says he's "consistently in awe" of the young hopeful.

Simon also reveals that iconic singer Paul Simon gave AGT and Kodi permission to perform the tune after seeing Kodi's Golden Buzzer-winning performance earlier this season. And that means a lot, because the legendary performer rarely gives permission for people to sing that famous single.

Kodi may have just won the entire season with that act. But we'll see if he makes it to the semifinals during tomorrow's results show.

To up the danger level even more than we could have ever predicted, the three-man danger group Bir Khalsa decided to not only make their stunts more dangerous, but to also bring on a new member of the team who seems to not be nearly as experienced.

As they hit the stage, the group are backed by flaming pillars and their first stunt is to give the blindfolded member of the group a chainsaw and task him with cutting a zucchini out of the mouth of the group's giant (oh yeah, one of them is a giant, if you don't know).

There's also some sledgehammer-on-watermelon smashing next to people's heads and some spear-stabbing, but nothing will ever top the chainsaw. Ever. For as long as this show is on the air.

Simon says it's "fantastically crazy" and Howie says it's "everything I love about this show." Gabrielle admits that they have managed to up the wow factor.

Luke Islam, a past Golden Buzzer winner, pays tribute to his beloved Broadway yet again with Monday's performance.

The 12-year-old entertainer delivers a bombastic, showy rendition of "You Will Be Found" from Dear Evan Hansen, and he can't stop smiling as the judges shower him with praise after his powerful act.

Howie tells Luke that he thinks we all just "watched your dream come true," and predicts that we will be seeing him performing on Broadway sooner than later. Gabrielle adds that the American public just "fell in love all over again," which feels about right.

It's hard to tell what the American public will feel about Luke's act, but it's hard to deny that he has a lot of legitimate talent.

Alex Dowis is a black light artist, but as we see in his pre-taped package, he began as a street artist who blended that love with an appreciation for theater.

That's why we are lucky enough to experience this epic performance. Starting with the Big Bang, going through the reign and extinction of the Dinosaurs and the next several million years of evolution, Alex tells the entire history of earth in a matter of minutes using just a screen and lights.

His art comes together in a mix of broad and tiny strokes, which keeps the bigger picture a secret until the last minute, when the weight and beauty of his imagery hits you like a brick. His work truly is real art.

Simon says he didn't get goosebumps this time around because it feels too much like something you might see at a science museum, however all the other judges (and the audience) unanimously disagree.

The adorable 13-year-old singer -- who is best known for having been stopped by Simon during both of her performances thus far and asked to sing a capella -- was eliminated during the Judge Cuts Round, but returned as Simon's wild card.

Her performance this time around doesn't have any of the overbearing backing tracks that were problematic in the past. Instead, she's singing with a live band and is embracing her southern roots with a fast-paced honky-tonk tune.

Simon says that, while he doesn't really like the song she chose, she's once again proven that she's an amazing vocalist. It's hard to tell if she'll move on to the semifinals, but her smile and her magnetic energy and charm should be enough to win the hearts and minds of the voting public.

Voices of Service are an amazing group of singers and an even more amazing group of people, and their quarterfinals performance show just how great all four of the entertainers are at commanding the stage and belting out moving high notes.

The quartet deliver an appropriately fiery rendition of Gavin DeGraw's "Fire" while backed by a military chorus, and are met with a standing ovation from everyone in the audience, including all four judges.

Simon predicts that they will connect with audiences and be voted into the next round, while Gabrielle is overcome with gratitude for the inspiration the group are giving to everyone in America.

Coming out with leather jackets -- mostly just as an excuse to have  even more clothing to strip off to the cheers from the audience -- the superhuman-esque Messoudi Brothers are bringing fire and danger to their act in a way we haven't seen before.

The three ripped siblings aren't just showing off new ways to climb all over each other in impossible positions like they have in weeks past. Instead, they are performing feats of acrobatic strength that should be impossible while on an elevated platform 20 feet off the ground.

Needless to say, the performance is sexy "on a whole other level" -- as Julianne says -- and it gets a lot of love from everyone... except Simon.

Apparently, Simon wants them to up the ante on the danger and he suggests including a tank filled with piranhas, as if the Messoudi Brothers lived in a bad James Bond film.

This time around, it's easy to ignore Simon and just appreciate the talent and skill that the Messoudi Brothers display in spades.

For Sophie Pecora's pre-taped package, the young songstress sings a tune written specifically about getting the Golden Buzzer earlier this season. It's super cute.

As for her actual performance, Sophie sings a more low-key original tune that starts off slow and is a wonderful display of her powerful voice and her youthful message. 

The song builds, however, to a powerful, painful tune about accepting yourself and has a lyric that actually gives me goosebumps ("If you're not happy where you are, you won't be happy in L.A.").

Julianne says she can't even find the words for what to say about her performance, and actually gets choked up as she tells Sophie that she "speaks truth" in her music. Gabrielle also says she's "such a rock star."

Simon -- who continues to clap even after everyone sits down -- has no end of praise for the simplicity and beauty of her tune and says, "I'm slightly in awe of you right now."

The biggest opponent the Emerald Belles have faced during their time on AGT has been Howie -- who irrationally set the bar for high-kicking dance acts at The Rockettes, which is wildly unfair.

This time around, the Emerald Belles kicked off their pre-taped package by taking some shots at Howie specifically -- and even getting him booed -- but their performance definitely proves they deserve to be in the quarterfinals.

Perfect timing, perfect song choices and event greater production values elevate the number beyond anything they did before. And as they end, the cheering is so loud Gabrielle can't even be heard over the screaming.

"I gotta say, I've been tough on you guys, but with your talent and our production... you blew the roof off the place," Howie finally admitted.

Carmen is a straight-up rocker!

After blowing the judges away during the Judge Cuts Round with her take on an iconic rock song, she returns to the Quarterfinals with an even more amazing rendition of Imagine Dragons' "Believer."

The song is an incredible showcase for both her vocal range and also her ability to 100 percent own a stage. There's no denying she deserves to be a star.

Simon says that the song started off shaky but marvels at how she is able to make it something special. Julianne also compliments how she put her "Carmen twist" on a song that is so famous and iconic.

Howie, however, didn't like the song choice, but he admits that she's one of the best singers of the season. Will people resonate with Carmen's choice? We'll have to wait till tomorrow to find out.

Impressionist Greg Morton has made it this far because he's funny, he's charismatic and he's talented. He has a brilliant way of recreating films through vocal mimicry, and tonight he's bringing out every trick in the book.

By taking on different vocal inflections, accents, and iconic performances  -- such as Sylvester Stallone's Rocky, Eddie Murphy's turn as Donkey in Shrek, and even Marlon Brando in The Godfather -- he manages to bring something new and exciting to the table yet again.

Morton proves that he can own a stage, which is something Simon praises him for. Meanwhile, Howie says that Greg is "the biggest variety show on Earth, all in one man," and he's absolutely right.

The girls of GFORCE want to be the next big thing in pop music, and for the live shows, they are excited to bring their own youthful form of girl power to the AGT stage.

Taking full advantage of the increased budget and stage designs available to contestants during the live rounds, GFORCE kicks off their flawlessly choreographed and lively number with a visit to a neon pink nail salon.

The song itself is the catchy kind of ear worm that pop groups have made a ton of money off of over the last two decades, and despite their young ages, they have the precision that takes other groups years to master.

Howie and Gabrielle are absolutely in love with their girl power message, and Julianne can't deal with how well-polished their performance is.

Simon admits that he doesn't like the song -- which earns him some boos -- but says that their number was "fearless" and advises them to stick together and develop their craft no matter what happens on the show.

12 acts, seven spots, four judges, two nights, one eventual winner!

Those are the important numbers to keep in mind as we kick off the quarterfinals tonight.

Another important number is three -- in that, for most contestants tonight, this will be the third time they'll be performing for the judges, and kicking it up yet another notch is no doubt going to be a challenge.