O Christmas Knight by Em Petrova

Tyler Knight, younger sister of the famed brothers who make up the Knight Ops team, ran off and joined the Marines, demanding to be treated as one of the guys and given all the accolades that have her big brothers thumping their chests daily. So a dark mission to clear a Middle Eastern village of a threat finally rewards her with the guts and glory she asked for. Until the tables are turned on her team, and she finds herself entrenched in a dangerous battle. She only hopes she can get home at all, never mind it’s Christmas and her family expects her.
Bo has always loved a strong woman, but a stubborn one? No way. After trying to rescue Tyler and her team, he finds the woman impossible—beautiful and sexy as hell, but impossible. Even though Tyler views backing down as wimpy, he has other priorities, and that is getting her home to her family alive.
It’s not long before Tyler’s stubborn pride has her running, but this time Bo’s having none of it, even if he has to dip into some very special Christmas magic to make her see how strong they are together.