After Ichigo defeats Yamwh, everything is peaceful. But that changes when Ichigo dies in his human body while saving a girl from a hit-and-run. His soul instead of going to the Soul Society, dissapears to a different world, with his memory wiped clean.
Yato finds his soul screaming and feels the souls pain, so he makes Ichigo his regalia. Several years later Ichigo tells Yato that he feels like something is calling him, and that he wants to find it. Reluctantly Yato lets him go, but they both agree to keep the contract. Two years later Yato finds Yukine and Hiyori. But a month after that Ichigo comes back.
But something else is brewing. In the Soul Society Kiskue finds where Ichigo's Soul has been transported and sends a small group after him. Problem is Ichigo doesn't recognize them plus one of their own becomes Yato's third regalia.
But this regalia might just succed in killing Yato, and Ichigo is not going to stand for that.