A mashup of two different tracks, "Sherlock (Clue + Note)" is often considered K-pop's first "hybrid remix".

[1][2] It features "a beat made out of a digitized kettle, little spurts of brass, and the recurring sound of shattered glass".

[3] "Sherlock (Clue + Note)" was Shinee's first Korean single since "Hello" (2010), following a year's absence due to touring and Japanese promotions.

[9] "Sherlock (Clue + Note)" received generally positive reviews from music critics.

[2][10] Writing for Dazed, Taylor Glasby praised the song's complexity and the "confrontational energy" of Shinee's performance.

[1] According to Billboard, ""Sherlock"" places a magnifying glass over the ways the Korean industry’s innovation is pushing music forward".

[30] In the U.S., it reached number four on Billboard World Digital Song Sales and charted for ten weeks.

[31] As of December 2017, "Sherlock (Clue + Note)" has received 30,000 downloads in the U.S., making it Shinee's fourth best-selling single in the country.

Testa tried to "create the illusion" that the members were "alone, retracing memories, their blurred bodies trailing behind as if trying to piece together their lives".