A love story about a rich boy, owner of a mansion (Len) and a maid (Rin). "Alcano" is Spanish for "alkane". An alkane is any saturated aliphatic hydrocarbon with the general formula CnH2n+2, and it's also called paraffin. In the song, the /ɾ/ (alveolar tap) sound, commonly used in Japanese, is sometimes replaced by the /r/ sound (alveolar trill, used in Spanish and other languages).