18.2.2 The Orphean Serenade

Once every 24 Achaean days, all Achaeans simultaneously experience the tranquil
music of the Orphean Serenade. This captivating song occurs exactly 365 times
during one Step, or cycle, of the Dance of the Vault. Every fourth Step,
however, the Dance is slightly prolonged and the serenade will occur 366 times.

(See also HELP VAULT)