The blistering summer heat of San Antonio, Texas, reveals a disturbing trend: a surge in fatal fentanyl overdoses among the homeless population. Someone is preying on the most vulnerable, leaving a trail of devastation in their wake.
Still reeling from the trauma of her husband's shooting, DEA Special Agent Marla Adams dives into the investigation after learning the victims have mysterious holes drilled into their bodies-something she has encountered before.
A chilling realization grips Marla as she discovers a vengeful doctor is fueled by a twisted sense of retribution against her. The doctor ventures into the labyrinthine stormwater system where darkness reigns at every turn. With each passing moment, the line between right and wrong blurs as the doctor plunges into the murky world of experimental medicine, unleashing an unorthodox procedure upon unwitting victims' minds to manufacture a formidable opponent against Marla.