On 8 October 2003, Agnes released her first adulthood's studio album, And the Story Goes, in which she worked with several prominent Indonesian producers and songwriters, including Ahmad Dhani, Melly Goeslaw, and Titi DJ. The album production took a year and a half, including the audition process for the dancers. According to her record label, Aquarius Musikindo, the album sold 35,000 copies before its official release. It was later certified double platinum after selling more than 300,000 copies. Four singles were released from the album: "Bilang Saja", "Indah", "Jera" and "Cinta Mati" (featuring Ahmad Dhani). The album received ten nominations at the 2004 Anugerah Musik Indonesia. Agnes won three awards for Best Pop Female Solo Artist, Best Dance/Techno Production Work, and Best Pop Duo/Group for her duet with Dhani. She also won Best Female Newcomer Artist at the 2004 Anugerah Planet Muzik in Singapore.
Mo has been noted as a powerful soprano with a vocal range spanning 4 octaves (B2 - C#6 - Bb6 - B6). Her songs can be classified as pop. She has stated that Aretha Franklin, Madonna, Michael Jackson, Fantasia, Brandy Norwood, Lauryn Hill, Mariah Carey, Christina Aguilera and Beyoncé have influenced her music. In addition to her singing skills, Mo is also known as excellent dancer and actress. She is the only Indonesian soloist with a personal dance group, known as Nezindahood. They auditioned during the development of her first album in 2003. She has also written some of her songs and produced her own music videos. She has been described as a perfectionist with a variety of talents by music critics.