Mother In Law Has Taken My Son.

I live in middle Tennessee with my wife and our 4 children. My wife has been struggling with substance abuse off and on for around 6 years now. She completed a 30 day stint in a Florida rehab at the beginning of April. Things were a little rocky between the two of us when she came home. I had lost all trust in her, and I was prepared to walk away. To give us each a little space, she agreed to go to sober living home that was geared towards helping women with families get back on their feet. She stayed for approximately two weeks and decided she missed her family too much and wanted to come home. Which she did. I didn’t necessarily agree to it, but as long as she wasn’t using, and I could tell that she wasn’t using, I didn’t see any problem with it. I was willing to give her that to see how it would go. So far, it has been fine….. except when she left this place her mother didn’t like it, and her mother has been pushing for her to go to this year-long place which is close to where she lives, in Alabama. For whatever reason my wife does not want to go to this place. I can’t say that I completely blame her, because it’s a year, and she would be away from her kids, it would also be tough for us to visit etc…. She just doesn’t feel comfortable going there. There’s a history with her mom, and it’s kind of a volatile relationship, and she just doesn’t want to go there. Anyway, on Friday my mother-in-law asked if she could get our two year old son so that we could have some time to work on our house, getting it cleaned up etc… It’s kind of disorganized and we are playing catch up. at first, I did not agree to this. I said no…. But my mother stepped in and said that she would take him to meet her, and that she would pick him up this weekend. Reluctantly and against our better judgment, we both agreed. So, this morning I get a text from her mother with a PDF that’s basically a court order that says that she has custody of my son until the 30th when there is a hearing scheduled. Can somebody tell me how this is possible? I’m just really confused as to how this is even legal and I really don’t know what to do. I don’t use drugs. My wife is in recovery. I believe this is a manipulation tactic to get my wife to go to this place that close to her(mother in law) that she’s been trying to get her to go to for some time now. There was no notice given to us that this was happening. And I’m not OK with my son staying with my mother-in-law or her husband… I know that he sells drugs and I know that he uses drugs as well. What do I need to do to get my son back? He doesn’t even live in Alabama. He lives in Tennessee. Please somebody, enlighten me.