Only those young enough can survive the pulse-pounding rush of tetra, a dangerous and addictive new drug that fuels a nine-minute burst of superhuman strength and speed. Alana West has been trained to use the drug so she can pursue the young criminals who abuse its power—criminals like the breakneck who nearly killed her kid brother. 

On tetra, Alana is unstoppable. The rush makes her an explosive blur as she surges through New York City, battling to bring down breaknecks before they leave more people dead or injured in their wake. But with the clock ticking down to her eighteenth birthday, Alana will soon be too old for the rush...when just one more dose will prove deadly. 

Supported only by her strong and steady handler, Tucker, Alana goes undercover, infiltrating an elite gang of breaknecks to stop the supply of their drug. But when Alana gets trapped on the wrong side of the law, she learns the breaknecks are not quite what they seem—especially Ethan, the artistic boy whose bottomless brown eyes seem to see the truth inside her. With her own dependency on tetra increasing, Alana must decide where her loyalties lie before the rush ends. Forever.