In 1998, she moved to the Gauss Entertainment recording label. In January, she led a main role to the Japanese television drama Tsumetai Tsuki. It was her first main role since Sugao no Mama de. She also performed theme song Kisei: Never Forget written by Yasuhiro Suzu. The single was released on 11 February. Nakamori states that the balance between low and high pitches were difficult for her to sing. The single debuted on rank 19 at Oricon Weekly Single Charts and sold 94k copies. B-side track is remastered version of album track Tsuki ga Aoku, which was previously released in studio album Shaker.
On 21 May 1998, she released her thirty-sixth single Konya Nagare Hoshi written by Keiko Utsumi. The single debuted at number 66 in Oricon Single Weekly Charts. The B-side track Arashi no Nakade has been written by Russian singer Origa. It is one of her worst-selling singles during two decades of her career.
On 17 June 1998, she released her eighteenth studio album Spoon. The album includes previously released two promotional singles. Five out of eleven songs were arranged by Ikurou Fujiwara. In the album booklet, she's credited as a main producer of the album. The album debuted at number 17 on Oricon Weekly Album Charts and charted for three weeks. Between 21 June and 17 July, Akina held national live tour Spoon Tour. The video footage was never released in DVD as of 2019.
On 23 September 1998, she released her 37th single Tomadoi written by Juni. Tomadoi was promoted as a theme song for Japanese television drama 39Sai no Aki. B-side track Good-bye tears was also promoted as a theme song for Japanese television drama Nananin no OL Sommelier in which Akina starred a minor role. The single debuted on number forty at Oricon Weekly Single Charts.
The chief of the Gauss Entertainment recording label, Kazuhiro Chiba caused Nakamori's stay in the label many troubles: in late 1998, was announced her special birthday in July 1999, however it was cancelled without announcement and the length of 8000 yen refund took one year. In early December, on the special press-con, said about Nakamori's existence as a troublemaker, who shouldn't exist in the music industry. In the end of press-con was announced contract cancelation scheduled on the December.