Two

Others have said it. Premise had some interesting potential. Freaky idea, wake up and you're sewn to another person, no idea what or how it happened. Ok. The reviews out here point out some key points - how were they drugged? How were they transported to some remote snow region? How did the father find them? Why wait until they are in their mid-30s to do what he did? Etc. Where the movie 100% lost me even if I wanted to forgive some of the other stuff I just mentioned is they cut themselves loose after shooting the guy that did it and he's dying on the floor. Women decides "hey, I'll just walk out in the freezing cold and snow naked for help" for what clearly would have been a very long time. Zero chance of surviving. No one decided to try the phone the guy had beside the cameras he had watching them? Bet that one worked. That aside, anyone with 0.00000001% of a brain in this situation would have used a towel or something to bandage the wound on their side from the cutting, then taken the dying guy's clothes and put them on before heading out into the snow for help so they wouldn't freeze to death in minutes. Implausible stupidity because the script wanted to hammer home the 'ying / yang / 2' concept to the viewer with the subtlety of a sledgehammer one last time. Problem is it takes the viewer completely out of the movie when relatively smart characters do something so ridiculously and obviously stupid.