Ichigo Kurosaki and Rukia Kuchiki meet a Soul Reaper they have never seen before, a girl named Senna, while chasing a wave of unidentified spirits over Karakura Town. Those spirits are Blanks, memoryless souls adrift in the Valley of Screams between the Human World and Soul Society, and Senna is bound to them. When a renegade group called the Dark Ones seizes her to force the two worlds together, Ichigo goes after her.