Secret Stories Heard From a Girl in an Opium Den (Korean: 아편굴 처녀가 들려준 이야기) is the debut studio album by South Korean electronica band Byul.org.

[1] Byul.org was formed in 2000 and became popular with the release of the EP series Monthly Vampire (월간 뱀파이어), but did not provide streaming and download services on its official music site.

[2][3] The first studio album began in 2005 at the suggestion of Burnt Toast Vinyl and was recorded for five years.

[5][6] Music webzine Tonplein named it the 18th best album of the 2010s and said "At the end of the 2010s, Secret Stories Heard From a Girl in an Opium Den will be an album that can remain as a nostalgia for the sentimental emotions of the past.

"[1] Hwang Inho of IZM described the album's track Bleu Bulb Light (푸른전구빛) as "It is a song that instantly melts the indifference to the texture of sound and makes me think about the musical worldview.