Answer the following Q with stream of consciousness. Context: One year later, Richard makes his way to his childhood home in Wisconsin to visit his twin sister Emma (Katherine Waterston). Richard returns home to find Emma widowed, pregnant and in debt. During his visit with his sister, Richard finds it difficult to put down the family dog. During this time Richard is tracked down by a former client who had hired Richard previously to carry out an assassination contract that was not honored. They corner Richard in the barn; during the ensuing struggle, Richard kills one of the gangsters, but the other one breaks Richard's hand and nearly kills him. Emma arrives just in time and kills the gangster, saving Richard's life. Richard realizes he is a danger to his sister and decides to go back to Atlantic City.

Question: who plays richard harrow sister on boardwalk empire?
To answer the question, consider the following: One year later, Richard makes his way to his childhood home in Wisconsin to visit his twin sister Emma (Katherine Waterston). Therefore, the final answer is Katherine Waterston.