Watch Bleach 231 titled “Byakuya, sakura totomo ni shō y” means “Byakuya, Disappearing with the Cherry Blossoms”
Ichigo finds Rukia Kuchiki injured in the world of the living, and that she is being attacked by a strange woman, who uses Rukia’s abilities. It is revealed that this woman is in fact Rukia’s zanpakutō, Sode no Shirayuki. Ichigo successfully forces the renegade zanpakutō into submission, and Sode no Shirayuki retreats back to Soul Society. Ichigo brings Rukia to Kisuke Urahara’s shop, where she reveals that the Soul Reapers’ zanpakutō’
Source: Mega video, Wiki