The blood between us

"Growing up, Adrien and his sister, Grace, competed viciously for everything. It wasn't easy being the adopted sibling, but Adrien tried to get along... When their scientist parents died in a terrible lab fire, there was nothing left to hold them together. After years apart, Adrien and Grace are now forced to reunite for their senior year... Being back around everyone he used to know causes Adrien to examine the person he's become, even while being back around Grace turns him into someone he doesn't want to be. But all those questions are cast aside when Adrien starts to suspect that Grace might be stealing their parents' research...or worse, that she had a hand in their deaths"--Dust jacket.