Michael Barnett and his wife Kristine were overjoyed when they expanded their family back in 2010 after adopting a six-year-old orphan from Ukraine.
However, the happy family soon had their world turned upside down.
The couple believed Natalia had a rare bone growth disorder when they adopted her, but claim she was actually an adult who "masqueraded as a child with intent to harm them".
In the shocking claims, which Natalia herself has denied, Michael and Kristine say Natalia abused them and even tried to kill her adoptive mother.
The family's story is now the subject of a brand new Investigation Discovery documentary, The Curious Case of Natalia Grace, and fans have been left conflicted over the "wild and unbelievable" tale.
Michael and his now-ex-wife Kristine were recently acquitted of neglect charges after leaving Natalia to live alone in an apartment while they moved to Canada.
In the documentary, the Barnetts allege that Natalia was 22 years old when they left her. Natalia insists she was just a child at the time.
Following episode one of the six-part documentary, viewers took to Twitter to share their thoughts.
"This Natalia Grace story is wild," one person wrote.
Another agreed, saying: "This whole story is unf***ing believable. The start of this, the closed adoption, how in the hell was the 1st adoptive family giving her up, not a flag to run?"
"Every single person in this story is weird AF #nataliagrace," a third viewer tweeted.
In 2012, the Barnett family successfully petitioned court to legally change Natalia's birth year from 2003 to 1989, changing her from an eight-year-old to a 22-year-old.
Speaking in the first episode of the explosive docuseries, Michael claims there were tell-tale signs which allegedly prove Natalia was in fact an adult.
Recalling the day they adopted Natalia, Michael said: "We get to the hotel that night, and Kristine’s going to give our brand new daughter a bath, and I hear a shout from the bathroom.
"This was a, 'I'm not playing around, come here right now, Michael,' shout."
Michael said Natalia "had full pubic hair", adding: "Is that possible? Is that even possible? Who the f**k is this person?"
Viewers said they have struggled to decide who to defend in the story, with multiple people seeming to be at fault.
"Started watching as soon as I saw your post, boy oh boy can't figure out who the bad person is or if it's several," one person commented.
Another said: "If I would've adopted a "6yr old" and I'm giving them a bath and they got full blown pubs, I'm taking em back cuz obvy the adoption agency lied."
A third viewer added: "Regardless of whether she was acting out, all these adults failed her.
"The parents in question are opportunists and showboaters. Also why was the little people org facilitating an under the table adoption? Why were so many couples going along with it??"
Natalia has a rare form of Dwarfism called Spondyloepiphyseal Dysplasia Congenita, and has previously denied the claims made by Michael and Kristine.
Speaking to Dr Phil, she said: "It's not true. It's not true at all. I just want people to hear my side."
Michael Barnett and his now ex-wife Kristine Barnett were charged in September 2019 with multiple counts of neglect, with him acquitted last fall.
And in March of this year, the charges against Kristina were dropped, according to WTHR.
Meanwhile, Natalia has found a new family and is living with her new adoptive parents Cynthia and Anton Mans and their five children.
The Curious Case of Natalia Grace will premiere across three consecutive nights on ID beginning Monday, May 29, airing nightly from 9-11 pm ET/PT.
