Til the Sun Dies

"You're not possible."
"What do you mean I'm not possible?" I demanded. "Of course I'm possible. I'm standing right here."
"I mean, you shouldn't exist."
In the small town of Redgate, on your eighteenth birthday, you are injected with a serum that can calculate how old you will be when you die. Your 'death age' appears on your left shoulder like a birthmark, and once it appears, it never fades.
The government is in charge of making sure everything runs smoothly, and for a girl like 18 year old Lia, well, its a fate worse than death if they find out about her.
When government worker, Jay, allows Lia to escape from the government, she runs across the border, ready to live the rest of her life on the run. If the government knew about her, the hunters would no doubt cross the border and track her down.
"What do you mean I shouldn't exist? Why am I impossible?" I asked, voice shaking. I didn't even dare to look at my left shoulder to see the number.
He gently touched my shoulder and then brought his eyes up to meet mine. "Because your death mark is an infinity sign."