"Higuumi Sound" formed by Ayane, who has sung many songs in the "Higurashi When They Cry" games and anime, and Otoya Volunteers of "Higurashi When They Cry, Umineko When They Cry". A collection of collaboration songs. In addition to Ayane's solo songs, Ayane and Sakuro Motoki's duet songs are included. Higurashi When They Cry It's the ultimate piece that colors the 20th anniversary.