"Yumekui" was used as the theme song to the movie "Tokyo Friends the Movie", which Otsuka starred in. The b-side, which is a ballad named "tears", was also used in the movie.
During the first week, the single debuted at #5 with 63,428 copies sold, making it Otsuka's lowest debut sales of the year. Although the single debuted with relatively low sales, it sold a total of 145,281 copies in 2006, making it the 66th best-selling single of the year.
Unlike most of Otsuka's previous singles, "Yumekui" only had one cover whereas usually there are two different ones; one for the CD-only version and one for the CD+DVD version.