Yakusoku no Yubi
The Promised Finger·約束の指
A long-standing legend tells of a prostitute who would sever a finger to present to a customer as proof of her devotion. Kotone, a servant, has fallen in love with Suzuka Ojou-sama and has given her a finger as a symbol of her affection. However, their relationship faces a challenge when Suzuka is expected to marry another.