Tracers - JJ Howard

Cam is a New York City bike messenger with no family and some dangerous
debts. While on a job a chance meeting with the mysterious
Nikki sends him head first into the intense world of parkour. Cam
joins the group of underground teens who have turned New York City
into their own personal playground- running, jumping and flying
through the city like an urban obstacle course.
The group offer Cam the chance to make some extra money... and the
opportunity to earn some cash, and being close to Nikki, makes
it impossible to say no. But Nikki is entangled with the brazen leader,
and when the stakes become life-or-death, Cam is torn between
following his heart and sacrificing everything to pay off his
debts.