By a chance

In the future after a huge chemical spill, millions wake up with enhanced abilities and senses, but the chemicals corrupt their brains. As time goes On GEAA is created, carefully genetically engineered humans who act as super soldiers. Every year they recruit high school seniors, and for the first time they come to Jane's school.

Jane Carson and Lucas Carson, both seniors and brother and sister. Lucas has been training his whole life to be a GEAA, but after one storming night all that changes.