Jen Burgess (Haylie Duff) has not had anything to do with her sister, Cassie (Jacy King), in years until she shows up out of the blue and lashes out at Jen in public. It leads to Cassie being placed into psychiatric care whilst Jen says she will take in Cassies twin, 15 year-old daughters Olivia and Quinn (Grace Van Dien) taking them home to her large home. When Cassie learns that her sister has become seriously wealthy she sets about using the twins, especially Olivia to manipulate Jen in to adopting them so that they can then murder her and inherit everything.
Kind aunt cares for creepy twins where one is more dominant and they are both very much being controlled by their mother who has a sinister plan. That is "Bad Twin" in a nutshell and I am sure you will guess that the crux of this movie is initially the twins getting to work on trying to make their aunt suffer and then turning things around to try and be adopted so that they can kill her and inherit her fortune. And to be honest it works because thanks to Grace Van Dien the twins are creepy and evil whilst at the same time Jacy King makes their mum that mix of crazy and crafty which equals dangerous.
Now I'm not going to tell you how "Bad Twin" plays out as to be honest it is worth watching but I am sure you can guess that with it being a made for TV movie it will end up in a certain dramatic way. But as such whilst Grace Van Dien is good at playing both twins and giving them some personality differences there is a lot of routine in the movie. One of those routine aspects is the nice performance of Haylie Duff as a nice character but in being so is forgettable. It is the same with Charlotte Graham who plays best friend Gail as whilst pleasant is equally as forgettable.
What this all boils down to is that "Bad Twin" ends up entertaining but because Grace Van Dien does a great job of playing the dual role with a mix of creepy, evil and out right sinister.