Mystery (alternatively Riddle) is the translated title of a 1994 Mandarin album 迷 (pinyin: Mí) recorded by Chinese singer Faye Wong as 'Wong Ching Man' when she was based in Hong Kong.
Although she had included a few Mandarin Chinese songs in her 1993 albums No Regrets and 100,000 Whys, Mystery was her first album recorded entirely in Mandarin rather than the Hong Kong majority dialect of Cantonese. The first track "I'm Willing" (or "I Do") was an instant hit single, and the album brought Wong to fame across the region of East Asia. The track "Cold War" is a cover of Tori Amos's "Silent All These Years"; Wong had already scored a hit with her Cantonese version of this song, which had been included in her 1993 album 100,000 Whys.
Despite the inclusion of Mandarin versions of that and other Cantonese songs, Mystery was a huge hit, selling over 800,000 in Taiwan alone.
^Shane Homan, Access All Eras: Tribute Bands and Global Pop Culture, 2006, p219. "Fung and Curtin (2002) have provided a reasonably comprehensive overview of Faye Wong's career up to 2001, ... song entitled 'Weak', with lyrics by Pan Li Yu, also about a relationship break-up, was included on her 1994 album Mystery."
^Anthony Fung and Michael Curtin, “The Anomalies of Being Faye (Wong): Gender Politics in Chinese Popular Music,” International Journal of Cultural Studies 5, no. 3 (September 2002) - album not mentioned by name -