Préludes No. 4: Les sons et les parfums tournent dans l'air du soir

"Moody piano notes tickled through the bridge's speakers."

- Halo: Ghosts of Onyx

Préludes No. 4: Les sons et les parfums tournent dans l'air du soir was a musical piece from Claude Debussy's Preludes, 24 pieces divided into two "Books." The name translates to "The sounds and fragrances swirl through the evening air," and is a reference to a poem by Charles Baudelaire, "Harmonie du soir".

The piece held some relevance for Doctor Catherine Halsey and Cortana. It was playing when Halsey transferred Cortana into an armored matrix on Reach before its fall. She later requested it from Jerrod when traveling aboard the Beatrice in 2552. In 2558, the piece was overheard by Fireteam Osiris as they reached the temple on Kamchatka where Halsey was being held. Later that month, Preludes was hummed by Cortana while she took control of Installation 07, evidently remembering the tune from her time under Halsey. A recursive audio memory of her singing was heard by John-117 as well during the Installation 07 conflict.

Halo game information
Preludes was included as the forty-first track of the Halo 5: Guardians Original Soundtrack. Alongside "On Deck", the track was released as an exclusive digital download for purchases of the soundtrack's limited edition. In-game, the track is heard during the opening cutscene for the game during Halsey's lab in CASTLE Base, and again as-played by Halsey during her temple in the first level, Osiris. The tune is later hummed by Cortana in the game's Legendary cutscene. In Halo Infinite, the tune is heard in the eleventh campaign mission, Nexus, as one of Cortana's clusters of recursive code on Installation 07.

The song can also be heard in the Warzone level Battle of Noctus, near the art structure inside the Monument.

List of appearances

 * Halo: Ghosts of Onyx
 * Halo 5: Guardians
 * Halo Infinite