Naisho no Pierced Earrings is releasing their first solo vocal album, "SHOWCASE." Known for their many rock ballads, including representative works like "Propose" and "CONFESSION," which embody a "LOVELY MELANCHOLIC" worldview, their first solo live concert, including additional performances, was completely sold out. In this album, the messages embedded in the lyrics and melodies are expressed through delicate vocals, allowing listeners to delve deeper into the world of the song.