Ikiryo: Vengeance and Justice - Akitada mysteries

Deeply distressed by his wife's adultery, Akitada returns to the capital to patch up his marriage and to help Superintendent Kobe with a case of poisoning. But before he can deal with either, the prime minister orders Akitada to save his dyinbg brother who is plagued by a vengeful spirit from his past. Unable to refuse, Akitada plays a dangerous game to bring justice to some of the dying man's victims.
Soon he is in even more deadly trouble when he tumbles into an affair with a dangerous woman and becomes the target of a cold-blooded assassin.