Elysium

Elysium is the name of a pod city, one of many. It's supposed to be a haven, somewhere where everyone's safe. That couldn't be more wrong.
Tessa Elwood is a privileged girl. Born into the upper class, everything is open to her. And with a dad as a councilman, the possibilities are endless. But she's sick, really sick. An illness she's had since she was two, and there's still no cure. It seems impossible that she even made it to nineteen. Her dad, worried for her health and his political ties, arranges with the Elector to have her marry his son. Tessa doesn't want any of it, she wants to escape. She's always wanted something more...or less?
Liam Heinz is a lower class orphan. He's lived in the orphanage his entire life. With no recollection of his parents, it doesn't really bother him. He's found his own family amongst the other kids. Elysium isn't kind to the lower class, especially the orphans. When his orphanage is disbanded, all the kid are kicked out into he outer fields, or the world outside the pod. He helps the others survive, keeps them going. To him there's nothing more important than the ones you love.
Tessa and Liam grow up together. Her mother volunteering at his orphanage. The two form an unlikely bond, one that can't be severed. Liam stays with Tessa through her illness, always making her smile. When Liam has to go, it leaves Tessa heartbroken. She can't go with him, she can't survive without her medicine. The two are split up, surely to never meet again.
When unlikely circumstances force Tessa to leave Elysium, she escapes into the outer fields. The very place she lost her best friend to. The very person she never thought she'd see again. But Liam's flourished in the outer fields. He and the other orphans have formed their own community, along with anyone else they could find. The two friends find each other again. A dream come true. But everything comes with a price.