My Great Sin

by JamieLovesDucks

Everyone in the London's shadow-world knows that if William Herondale cared for anyone other than himself, it was James Carstairs. The two teen Parabatai are inseparable, even they know they are. but what happens when a series of innocent incidents in their homeland, Idris.. lead to other, less innocent incidents? love isn't always searched for, sometimes it finds you instead...

1. Prologue

My Great Sin

Entreat me not to leave thee,

or return from following after thee -

for whither thou goest, I will go; and

where thou lodgest, I will lodge.

Thy people shall be my people,

and thy God, my God.

Where thou dies, will I die, and there will I be buried:

The Angel do so to me, and more also,

If aught but death part thee and me.

- The oath of the Parabatai

Prologue: London, June 1877

'' Jem, Will! Have you packed everything that you'll be needing?'' Charlotte Branwell called out, walking out onto the stone stairs at the front of the London institute. William Herondale was walking out of the institute with a very unflattering scowl across his face, closely followed by James Carstairs who wore a more pleasant expression. The two boys made their way down after the woman. At the bottom by the carriage awaited her Husband, Henry, who kissed her lightly before helping his short angel into the carriage. He then patted the two young boys on the shoulder, earning a smile from Jem and no reaction from Will as the two helped them selves into the carriage driven by Thomas.

For the first several long moments the trio remained silent. Only when the institute disappeared around the corner did Charlotte sigh in exasperation and said,'' Oh, what is it now Will?''. William, who has spent the time with arms crossed over his chest and frowning deeply, glared daggers in her direction.'' I do not see the reasoning by which I am required to go on the voyage with you, charlotte''. The woman sighed again, rubbing her temples as if her head was in pain, while Jem simply rolled his eyes. No one, perhaps with the exception of Jem ever got used to the melodramatic nature of the teen (though maybe Jem was simply a patient enough person to not let it bother him so much).'' You are coming with me...'' she began, in a way you would word out everything for a small child.''...because I don't trust you being alone in the institute without me''. Will threw up his arms.'' What have I ever done to earn this distrust?''.

'' Well..'' Jem began, to his own amusement.'' ..remember how last month you practically burned down the weapons room?''

'' I was simply trying out Henry's new fire-weapons''. Yet again Charlotte sighed.'' I still cannot believe he let you near these weapons..''. Jem cleared his throat.'' And remember how just a week before that Charlotte had an Enclave meeting and you stormed into the room and started accusing all the members of the Enclave of being infected with demon pox?''.

'' Gideon Lightwood had all the sympto-''

'' Will..'' Jem said calmly and patiently.'' demon pox isn't a real disease... I am quite certain we talked about it before''. Will frowns again but then groans with annoyance.'' I don't see how any of this links? I wasn't alone then''

'' Exactly'' said Charlotte.'' This is precisely why I can't let you be alone in the institute''.

'' And Jem?'' Will asked. Charlotte glanced at the sliver boy who smiled at her kindly.'' Jem is you're parabatai, Will and besides, someone has to keep an eye on you in Idris''.

'' You think I would what? Burn down Alicante? climb the demon towers?''.

'' The fact that you are suggesting such things makes me even more worried''. At this he smirked.'' Jem..'' she says though doesn't look over at him.'' Do keep an eye on him for these two days, please''. The smile that never left his face only brightened.'' Charlotte, when was it that I haven't kept an eye on him these past 4 years?''. He then glances over at Will, and for the first time this morning Will smiled.'' when indeed''.