Disclaimer:

After trying to help Simon in bringing Clary back to the mundane world , Tamsin finds herself being dragged deeper and deeper into a world that she never knew existed. Despite being in denial to the new world around her Tamsin soon realises that she has a big part to play in the world of shadowhunters and downworlders.

Based off of Shadowhunters tv show {season 1) and maybe throwing in some parts from the other TMI books :)
As everyone always has to say "I do not in any way shape or form own any of this stuff blah blah blah only my own characters like Tamsin are owned by me"