Another Winner by Karpov & Kinrade
This is the story of Sky, a firefighter, who lost her Mother during the birth of her last half-sibling, Kara, who she has raised as her own baby, while mothering the two young boys her mother left behind as well, because their father is a useless alcoholic. If it wasn't for Sky, the county would have removed the kids from the home long ago!
To help make ends meet, her best friend and one of the paramedics from the station, lives with them and helps with rent and other bills. The kids' father doesn't pay for a thing, he just makes a mess, yells at everyone, threatens to kick her out every other day, and stumbles in drunk whenever he does show up.
When a strange man comes to the door asking for the kids' father, saying he owes him a debt, and that he intends to collect, it scares Sky, but she has no idea how bad things can get.
The next day, he asks for him again, and when she tells him honestly that she really doesn't know where he is. He threatens her. She calls the police. But then realizes when she gives a description, the officer doesn't record it correctly. Then she finds their cat, killed in the front porch. Things go from bad to worse when she finds out her step-dad basically sold his baby girl to pay a gambling debt! She's outraged and then panicked when she realizes this isn't a joke, and this freaky guy is going to steal her baby, the baby she's loved and cared for since birth, her infant sister, Kara!
He comes for her, and she fights him, but she loses, even with help from a guy from another world who is after the same guy!
There's nothing else that Sky can do but to beg this guy, Kaden, to take her with him, to his world, so she can search for Pike, the guy who took her baby. But the only way he agrees is if she agrees to go into training to become an Ashknight, so she will know how to defend herself the right way. Because you see, Sky has some secret powers, her Mother made her wear a leather band on her wrist to cover up, her identity to those who would recognize her power, and to keep it in check. But when she was trying to fight against Pike, she accidentally hurt her little brother, burning him. So she knows she has no choice but to leave, to find Kara, but also, to keep the boys safe. Leaving them in the care of her best friend, she follows Kaden into the unknown.