TID: Jem + Tessa crime au:

When Tessa Gray murders someone in self defense, she knows she can no longer return to her normal life . While on the run from the police she meets Jem Carstairs, the leader to a gang. Death, drugs and danger are what people associate Jem with.

Jem takes Tessa under his wing and teaches her his world of crime and corruption. 

But as time goes on, Jem falls in love with Tessa and starts to  feel the slow burn of shame and regret as he is tormented with the fact that he has ruined Tessa’s innocence as he watches her sink into darkness. 

The Infernal Devices AU (4/??) >>> Tessa gets possessed by Lilith in CP2

“The Silent City?” Tessa asked quietly, somehow gathering everyones attention in the blink of an eye. “How would the Brotherhood help me to stop Lilith?”

Charlottes eyes darted around the room, as if in search of some help but Tessa waited patiently and when she turned back the young girl could see that Charlotte had yet to look her in the eye. “Well,” She began, shuffling papers on the desk in what Tessa supposed was an attempt to look busy. “The ritual to be done to you normally only placed on Shadowhunters- but I figure that if you can handle Lilith’s rune of possession, then you may be able to handle the markings given to Nephilim children that are supplied to avoid this sort of occurrence.”

“Absolutely not!” Will skyrocketed up from the chair, shocking the London Institute’s inhabitants within the room. “Tessa is not a Shadowhunter! Lilith is a demon and Tessa is part demon, of course she could handle runes placed by her. But Downworlders can’t handle angelic runes Charlotte, she’ll die.”

Charlotte seemed to just get paler by the second. “And the Clave will kill her if they find out-so we don’t have a choice, do we? I know it is dangerous but it is the only chance for Tessa to… Tessa?”

Everyone looked around the room to see the girl in question rifling through files on Charlottes desk at a seemingly inhumane speed.

“Tessa?” Jem asked tentatively.

“There has to be another way Charlotte- don’t be dull." She giggled. "It is as if you are turning into Henry. The Silent City won’t help me, only as much as the Clave has assisted you, which I gather isn’t a lot if you're still under scrutiny even after receiving dear old Benedict's words of support.  Oh, I do quite miss Mr Lightwood, thought I’m sure he was prettier as a worm.”

The silver haired boy stood up, knowing that he may be able to get through to his fiancee when she was in this state. He had done it before and he would do it again. Anything to keep the real Tessa safe.  By the looks of determination on everybody else’s faces, even Gideon, Cecily and Gabriel who had only known Tessa a short time, they were all going to try and get the real Tessa back. Permanently.

Whether Lilith liked it or not.