Here is the promo for the last episode of season one
https://youtu.be/P4VVGvXmrDg
I REALLY CANT WAIT TO SEE THE BIG PLOT TWIST!!!

In the preview,  it shows Clary with graybook and then 2 people are like holding Simon and Izzy like they're something somebody will trade to get something back. That was confusing so I was basically saying that  Simon and Izzy are trading bargains. But, Jace is across from Valentine and Valentine says "you have so much to learn" so maybe Valentine wants jace to come with him, so maybe he does and that's the plot twist...

Please comment your ideas on what you think the plot twist is going to be!