Danny is awakened by a knock at the door. It's his ex-wife Rachel. Grace hasn't come home and can't be reached by phone. McGarrett meets Danny and Rachel at the hospital. Grace and her friend Katie are both in critical condition. Grace was going double the speed limit so HPD has to open an investigation. Katie's father blames Grace for the accident. Grace has to undergo neurosurgery. Tani discovers that her brother Koa got beaten up when he went out looking for an outpatient, Alana, who disappeared. Tani seeks out Alana's ex Dylan, who assaulted Koa, and works him over. Dylan said Alana had stopped by to make amends, but he hadn't seen her since. The accident scene reveals that someone forced Grace off the road. Grace had received a threatening text message from a girl named Cameron. Cameron had downloaded a nude selfie of Katie, showing it around, then Grace dumps that phone in a beer. Based on the oil found at the scene, the perp was driving an older car. Grace hemorrhages during surgery. At Kelsey Yang's house, Tani finds both Alana and Kelsey overdosed on heroin. Koa doesn't buy it since Alana was afraid of needles. Koa finds a supply of oxy in the toilet thank. Koa thinks Alana was trying to implicate a doctor selling oxy. In surveillance footage, Grace tells off a man hitting on her at a diner, and he follows them. They track his car, then McGarrett takes him and it for a test drive. Steve terrifies him and he confesses. Tani goes undercover to bust the doctor, but he claims he had nothing to do with the murders. The cartel behind the clinic had them killed. Grace comes out of surgery OK and is home a week later.