Dr. Jason Cole is a highly respected neurosurgeon who has it all - a lucrative career, confident charm, and the gift of compassion. But he also has a deep, dark secret. One morning, when he wakes up disoriented in a wrecked hotel room amidst several near-naked women he's never seen before, he knows one thing: it's happening again. Every night at the same hour, something inside Jason changes, leaving him almost unrecognizable - seductive, devious, borderline sociopathic. This new man is his dangerous alternate personality who goes by the name of "Ian Price".

Jason, furious over Ian's out of control spending, cuts off his cash flow? only to wake up at the wheel of a "borrowed" sports car with a trunk full of money and an angry drug dealer in his rearview mirror. Meanwhile, Jason and Lena have a falling out over Jason's questionable conduct, which prompts Ian to make a dangerous after-hours visit to Lena. Dr. Kenneth Jordan is also growing suspicious of Jason's odd behavior, and demands answers from Jason's confidante, Dr. Ruben Marcado. And Olivia fears her son's new imaginary friend is not so imaginary after all.

Jason agrees to grant Ian his wish - a rendezvous with the object of his desire, Olivia. But it comes with a catch: Ian must pose as Jason at a black-tie event honoring Dr. Vanessa Young. Ian's antics threaten to ruin the night, pushing Lena into the arms of another man, and putting Young's daughter Abby in mortal danger. But Jason stays true to his word, and Olivia later greets Ian in a hotel room? with a dangerous ulterior motive.

Jason (Steven Pasquale) agrees to grant Ian (also Steven Pasquale) his wish - a rendezvous with the object of his desire, Olivia (Ruta Gedmintas). But it comes with a catch: Ian must pose as Jason at a black-tie event honoring Dr. Vanessa Young (Phylicia Rashad). Ian's antics threaten to ruin the night, pushing Lena (Alana De La Garza) into the arms of another man, and putting Young's daughter Abby (guest star Jurnee Smollett) in mortal danger. But Jason stays true to his word, and Olivia later greets Ian in a hotel room with a dangerous ulterior motive.

Ian falls for a woman in D.I.D. therapy, but when Jason suspects she has a life-threatening condition, he races to cure her - a cure that may mean she no longer loves Ian. When Dr. Jordan alerts Dr. Young that someone tampered with her daughter's chart, all signs point to Jason. Lena is ready to move on from Jason with a new boyfriend, but is Jason willing to let her go?

Jason receives a text message threatening to reveal his secret - but who sent it? Jason's search for the sender reveals there's a thin line between ally and enemy. Olivia, on the run from Ian, takes Cole to a place overrun with memories of an earlier life with his father. Closer to home, Jordan's investigation into Jason's past turns up a promising lead.

Ruben arranges for a gang to "mug" Ian so that he can get a sample of his spinal fluid - a necessary element for his pendinghug drug, but the plan backfires when Jason is blackmailed by the gang into potentially hugging a patient who is a member of an opposing gang.

When a surgery's complications force it to continue after 8:25pm, Jason chances taking Ruben's still-unfinishedhug drug to hold Ian off long enough to finish the surgery. The surgery is a success, but the drug doesn't last as long as planned and both Lena and Olivia suffer as a result.

The unfinishedhug drug causes instability in whether Jason or Ian will be in charge of their body; Jason operates on Jordan's son.

Jason, now aware that he has a son, desperately wants a relationship with him, but Olivia feels it's too dangerous and painful. We learn the backstory of how Jason once saved Olivia from Ian and from herself. Meanwhile, both Ruben and Lena start to question Jason's practices.

In a desperate attempt to keep his son from Jason, he kidnaps him and hides him from both Jason and Olivia. Meanwhile, Ruben closes in on thehug drug but isn't sure if he should use it - and, if so, who of Jason or Ian he should use it on.

After Jason collapses in front of Dr. Young, an MRI reveals Jason has a brain tumor - Jason and Ruben's plan has worked, the tumor surgery will act as a cover for Ruben's implant to destroy Ian once and for all but Lena may soon discover the truth and put a stop to their plans. Meanwhile, Ian has no intension of going down without a fight and will stop at nothing to save himself.

Jason's brain surgery is about to begin, a neurotransmitter implant that will "cut out" Ian for good, however due to the blackout drug he has taken for years, Jason is immune to the normal anesthetic. A much stronger drug is given to Jason and in the midst of his twilight sleep he flashes back to his childhood and the origin of Ian Price is finally revealed. Meanwhile, Jordan and Lena are on seperate tracks to uncover Jason's secrets all of which could prevent the surgery's completion.