Natalia Grace and adoptive father Michael Barnett are Charles H. Sloancoming face to face for the first time since their shocking story took the world by storm.

In a new sneak peek at the upcoming Investigation Discovery docu-series The Curious Case of Natalia Grace: Natalia Speaks, the Ukrainian orphan—who was adopted by Michael and his ex-wife Kristine Barnett in 2010 when she was 6 years old and who suffers from spondyloepiphyseal dysplasia congenita, a rare genetic disorder—finally gets some answers from her estranged dad about why the former couple believed she was actually an adult sociopath who tried to harm them.

Natalia's first question during the tense confrontation? "Why did you adopt me in the first place?" 

For Michael's part, he points the finger and Kristine. "Many of these questions there's not going to be a single answer to," he replies in the Dec. 28 preview. "I've learned recently you and I have the same monster: Kristine. And we are here because we both were incredible victims of an other-worldly type of abuse."

Michael alleges he "was exceptionally controlled and put down and threatened" by Kristine, adding, "Anything that was who I was was ripped from me and I was guided and instructed to be exactly what she wanted me to be."

When Natalia questions "what do you mean by 'threatened?'" Michael claims Kristine's "favorite threat was taking" their son Jacob away from him.

"I tried to leave her no less than 10 times," he continues. "I ended up in the hospital regularly for it."

Michael filed for divorce from Kristine in 2014 after almost 20 years of marriage following their accusations that Natalia was dangerous and trying to harm members of their family.

One year later, both of them were charged with multiple counts of neglect after moving to Ontario, Canada and leaving Natalia in an apartment they had rented in Lafayette, Ind.

See Natalia and Michael's tense reunion in the preview above.

The Curious Case of Natalia Grace: Natalia Speaks will debut on three consecutive nights on ID starting Jan. 1 at 9 p.m.

For more true crime updates on your need-to-know cases, head to Oxygen.com.