War Of Hearts

"I can't help but love you, Even though I try not to. I can't help but want you, I know that I'd die without you."

Maryse lightwood had a secret that could potentially ruin her family, her oldest, Alexandra wasn't a lightwood. She was a Mikaelson.

Or

Fate decides to unite the shadowhunter and downworlder communities, reveal a few well kept secrets, and maybe just bring a family together in the process, all by showing people the life of Alexandra Lightwood.