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The SM Entertainment�boys honestly opened up about what really went through their minds during their long training periods prior to their debut. Taemin revealed that he used to be tone deaf and Kai also revealed how he felt when he would see trainees make their debut before him as well as his practice methods. We will also get to see Kai's audition footage as well.

This documentary will focus on the saying that to become a professional, one must put in ten thousand hours of practice. To see how true this is, the show will interview various experts in the field of education and medicine, and talk to Kai and Taemin about their long training periods.

In the preview released for the show, Taemin shared, "[Others would tell me] Your voice is not meant for singing." Kai also shared, "I probably [practiced] for about 20,000 hours."

Stay tuned for the documentary on the 16th at 11:15 PM KST!