Grace Yang is first introduced as the court-appointed mediator in the custody battle for Josslyn Jacks between her parents Carly Benson and Jasper Jacks. Her job is to observe both parents with Josslyn and interview them, and then make a suggestion to the judge as to which parent she believes would be the more appropriate parent for Joss to live with. Carly, however, initially becomes concerned with Grace's true motives when Grace refuses to interview or observe her with Josslyn. Instead, Grace meets with Carly one time, when she meets with both Carly and Jax together. It is apparent, however, that Jax has met with Grace on more than one occasion. At the hearing with the judge, Grace makes the suggestion that Joss should go into the custody of Jax, and Carly flips out. She cites that Grace had not spoken to her but for the one time, and that there is no way that she can possibly make the decision based on one chat with her. After the hearing, Carly tells Sonny what happened.
Sonny takes it upon himself to fix this problem. He finds out that Jax paid Grace to win him custody. Sonny then has a conversation with Grace telling her he's aware of this and he blackmails her. He tells Grace that he won't tell anyone Jax paid her off if she helps him frame Jax so that Carly will when custody.
Grace goes over to Jax's hotel room. She slips something into his drink, and when Jax becomes disoriented and starts yelling at her to tell him what she gave him, she starts yelling for him to get away from her. Grace rips her clothing, yells, screams, and runs to and locks herself in the bathroom. She calls 911 on her cell and tells them that Jax attacked her. Meanwhile, Jax is screaming at her and banging on the door. The police come and Jax is arrested. It is revealed that drugs were found in Jax's hotel room as well, and neighbors who heard screaming and loud noises serve as witnesses. Ultimately, Jax is found to be an unfit parent, and Carly is granted full custody of Josslyn.