The second semi finals round on “America's Got Talent” Season 12 would require “nothing less than perfection,” as host Tyra Banks reminded contestants on September 12. Decked in yet another shade of gold, Tyra didn't waste any time getting to the performances.

Celine Tam took the stage first, and took on a big song with the theme from “Moana,” “How Far I’ll Go.” There are times when this nine-year-old's size seems almost invisible surrounded by big stage sets, but her voice is undeniable. Simon Cowell opened remarks with warm thoughts for hurricane victims and then credited Tam with making a “massive step up” in this performance.

Heidi Klum also told Celine that her voice was “crystal clear” and that she was a star. Mel B expressed her love for the singer but said that the song was “too musical” to show off her voice in this case. There would be ten more artists to thrill and surprise from the stage, but only five can become finalists.

Magical prediction and more music

Colin Cloud set out to clear out the confusion from his quarterfinals performance, and still pull off a stunner. Drawing from thousands of public responses to offer random words via twitter for the judges to choose for this feat, the master forensic thought student managed to predict that the words chosen would come down to Ellen, Rome, and cheese. From various places and times, Cloud proved himself to be part of the whole process, never being detected.

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Simon Cowell called the entire spectacle “spooky, creepy, and weird.” Howie Mandel implored America to vote, and the ladies were also awestruck

Christian Guardino commented in his profile that he was “on ‘America's Got Talent’ for a reason.” The singer displayed a huge part of that reason when he sang Marvin Gaye's classic, “What's Going On.” It was the best-ever moment for the young man who was once blind, and his passionate expression and powerful delivery will certainly make this a performance to remember. “You’re going on,” Howie Mandel raved, as Mel B chimed in with “that is how you kill it.” Heidi Klum added, “I love you so much,” and Simon Cowell capped the commentary in noting that Christian was “fantastic” and suggesting that he go back and listen to his performance with eyes closed to sense its power.

All together now

Air Force singers and servicemen, In The Stairwell, came on in unison to give their best ever performance on “America's Got Talent” with a patriotic turn on Ed Sheeran's “Castle on the Hill.” The strength of their voices and their unity was absolutely stirring and rich in sincerity.

Mel B was moved to tears, telling “her boys” how much they deserved to be there. Simon Cowell also celebrated the improvement of the group and gave his endorsement for the finals. Howie Mandel has never really liked this group, but this performance prompted him to “love it.”

Dancer Merrick Hanna made things personal with his pre-performance story of how robots helped him emerge from his shell. Howie Mandel appreciated that story even more than the performance of the robot boy, and Simon Cowell reminded Merrick of how much the panel came to know him as a “fun guy.” Heidi Klum reminisced on how far Hanna had come through the competition. This performance was good, but just not different enough at this stage of the competition.

Mandy Harvey gave a true feel of her silent world in her profile, and then poured her heart into a bluesy, jazzy, and beautiful original song, “Release Me.” The hearing-impaired singer has often expressed that music is felt, not simply heard, and her emotion came through every note of the mournful tune with truly original style. Simon Cowell told Mandy that her performance was “as good as I've ever heard in a competition.” Howie Mandel commented that “you transcend hearing” to the singer. Heidi Klum told Mandy that this was her best performance, and Mel B commended it as “so powerful.” This performer has the talent, the passion, and the something different to stay in music for a very long time. Tyra Banks teased that Mandy was “bringing the sexy,” too.

Topping the night off

The Pompeyo Family and their menagerie of precious dogs were joyful as ever in their Arctic-themed routine. They were the judges choice to come back as a wild card, and they delivered their characteristic dose of big warm love from the stage. Howie Mandel teased that they had taken Mel B's wardrobe for the week as inspiration. Simon Cowell said he sometimes struggled because these pets “don't look like dogs. Heidi Klum simply related how much “joy, love, and happiness” flowed from every performance. Regardless of America's vote in this season, this act will be seen by much of America for a long, long while.

Acrobatic dancers Diavolo wanted to be “elegant gladiators” in their display of movements and jumps from cubes, spheres, and triangles in their last try for the “America's Got Talent” finals. The judges and the audience seemed wowed, with Heidi Klum praising that “you came to win. This is a million-dollar act!” Mel B yelled out her “What just happened!” Simon Cowell told the group that they had been Vegas caliber through every performance.

Kechi was at her inspirational best in her offering in song to her mother, “Don't Worry About Me.” Stripped-down and pure, the offering was a beautiful expression of the mother-daughter bond through its promise that “we rise together.” One of the most moving moments was when the camera turned to Mel B's quiet tears of emotion. Simon Cowell called the moment “magic, magic, magic” and Howie Mandel wanted to hug the singer. Heidi Klum praised that Kechi “ruled the stage like a queen,” and Mel B reminded that her voice brings “wonders” to people. Now that the survivor has found her stage, the world will treasure her forever.

Techno-illuminators, Light Balance, put on their fast and flashy best, and Howie Mandel remains a raving fan, insisting “this is a million-dollar act,” with all the panel approving. It remains to be seen whether this week's dance and light display is distinctive enough to draw in more votes. That choice must come from the fingers of fans who click and dial-in votes.

Angelica Hale was the closer for these “America's Got Talent” semifinals, and she went big with David Guetta’s hit, “Without You.” Angelica has made no secret that she wants to take it all in this competition. There is a surreal feeling when these wrenching notes of love come from the voice and body of a 10-year-old, but she is a champion at hitting the big notes. She knows it. The judges know it, and America hears it. This young singer has some tough competitors, but she's still going far.

Predictions for five acts going to finals:

Christian Guardino

Mandy Harvey

Diavolo

Kechi

Angelica Hale

Season 12 finals start next week.