The death of their father sent Irish twins Nori and Nadia “Nadi” Porter on two different paths in life. Nori found solace in furthering her life through education, while Nadi found peace in the streets with her longtime boyfriend, Kelz.

When one of Kelz's high-profile robberies returns and leaves him dead in Nadi’s arms, life as she knows it comes to a halt. That is, until she figures out a way to get the ball rolling again.
 
Nori wants no part in her sister’s scandalous life. However, with no real money coming in and tuition due, she seems to have no choice. She agrees to help her sister continue where Kelz left off. But when a robbery goes wrong, and they end up on the bad side of a drug lord, they have no choice but to become his hired hands. To repay their debt, he asks an impossible task of them. He sends them on the Murder Express.