Between Truth and Deception

Quick answer: 8 episodes, English original audio, and episodes 1–8 play right here tonight.

The woman thought she had the happiest family and the most loving parents, but unexpectedly, her mother forced her father to death with a mysterious letter on the anniversary of his death. In order to learn the truth, she married her beloved and had a child at her mother's request. Unexpectedly, on the day of delivery, her beloved was also forced to death by her mother with the same letter.

The woman hated her mother even more and asked for the truth many times but got nothing. Out of desperation, she threatened suicide in order to get at the truth. When finally agreed upon by her mother to reveal it all, she suddenly disappeared without explanation leaving everything back into a dead end until when twin sister appeared; together they joined forces in this game that eventually uncovered their mother’s secret.