The Holy Grail of Eris, Vol. 1 (manga)

Connie is a viscount’s daughter with little notable attributesbesides her sincerity, so when she’s suddenly framed for a crime shedidn’t commit, it seems like the end of the line for her—until theghost of Scarlet Castiel, an infamous villainess who was executed ten years ago,swoops in and clears her name. In exchange, Connie resolves to solve the mysterybehind Scarlet’s untimely death...and in the process, uncovers aconspiracy that still haunts the present!