Do No Harm is a medical drama series that follows Dr. Jason Cole, a successful and respected neurosurgeon who harbors a dangerous and terrifying secret. Every night at 8:30 PM, he suffers from a rare dissociative identity disorder that causes his malevolent, sociopathic alter ego, Ian Price, to take over his body for twelve hours. While Jason is compassionate and dedicated to saving lives, Ian is ruthless, manipulative, and willing to ruin Jason's personal and professional life to satisfy his own desires. As Ian begins to push the boundaries of their shared existence, Jason must race against time each day to find a permanent cure, protect the people he loves, and prevent Ian from committing irreversible crimes.