Grace's world crumbles as her family remains in jeopardy, the FBI closes in and Constantine reveals something that rocks her to the core. Meanwhile, longtime mobster Al Trapani becomes increasingly involved in Constantine's business, and Franco's secret leaks. As the walls begin to close in on Grace and the duality of her life cuts deeper than ever before, she makes a desperate attempt to settle her role in both worlds.

As Constantine attempts to reconnect with his estranged son Garrett, who is deep in debt to the ruthless Nogales Cartel, he enlists the help of his Chicago mob colleague, Al Trapani. As payback for the favor, Constantine orders Grace to diagnose Trapani's girlfriend, a patient with a shocking secret who is experiencing inexplicable pains.

When a champagne bomb is delivered to Constantine, he and Celeste go on high alert to determine who wants him dead. Meanwhile, Nate turns to Grace after he accidentally jeopardizes a mobster's valuable racehorse. Back at Roosevelt Medical Center, Grace is tapped to treat Brett's estranged brother, Jack Hanson, following a severe cycling accident.

Spirits intensify at Roosevelt Medical Center when Dr. Devlin and Dr. Robinson treat a priest who was bitten in the face during an exorcism of a demon. After Constantine learns that newcomer Russell King has his eye on taking over downtown, he consults Celeste and Al Trapani to help him evaluate the risks and rewards of consolidating the power in Chicago. Meanwhile, Dr. Devlin dives deeper into the fold when Nate calls her into action to aide a runaway who may have witnessed a murder.

When Franco tells master thief Russell King, who is in Chicago for a big heist, to show up at Roosevelt Medical and request Dr. Devlin's treatment for a flare-up of back pain, it's discovered that he needs immediate surgery. Meanwhile, Constantine becomes suspicious when he learns that Russell has resurfaced on his turf. An intense race against time for Grace, Constantine and Russell unfolds as the lucrative crime looms and lives are on the line.

In an attempt to form a coalition of mob factions, Constantine enlists Celeste LaPree, his old girlfriend and former call girl-turned-madam, now married to a hypochondriac mafia boss who runs Chicago's Northside. Meanwhile, Franco has a shocking revelation for Grace, forcing her to make some pivotal decisions about love and loyalty.

When two innocent bystanders are caught up in an ambush meant for Franco and the rest of Moretti's crew, Grace joins the action. As the war between Moretti and Constantine escalates, Grace makes a critical move in an attempt to end the feud.

Emotions reach a breaking point when Grace and Brett's relationship shows signs of strain due to their demanding and hectic schedules. Meanwhile, Grace finds herself in a perilous situation when mob boss Paul Moretti takes matters into his own hands.

As she fights for a critically ill woman's heart transplant, Dr. Grace Devlin is asked by Constantine to kill her patient's estranged and imprisoned father in order to get the organ she needs to save her life.

Dr. Grace Devlin must save the life of an old friend injured in a pub-crawl accident, while tasked by Constantine with delivering the child of a pregnant call girl. Meanwhile, Franco has to track down a young woman whose whereabouts are crucial to his boss.

After treating a family that was involved in a fatal car accident, Dr. Grace Devlin reels when she is ordered by Constantine to tend to the driver of the deadly hit-and-run. Meanwhile, someone from Grace's neighborhood is brought into the psych ward after a bar fight, and Nate makes a critical move.

As Grace's ties to Chicago's Southside mob intensify, Constantine sends her to meet slain mob boss Paul Moretti's former rival, Donte Amato, who's suffering from an undiagnosed life-threatening condition. Meanwhile, romance at Roosevelt Medical Center pulses when Grace collaborates on a heart-wrenching case with Dr. Robinson involving a young bride experiencing severe mood swings.

For most physicians, the Hippocratic oath is sacred. But for Dr. Grace Devlin (Jordana Spiro), a top resident at Chicago's Roosevelt Medical Center who is indebted to the mafia, saving lives isn't her only concern. In this fast-paced medical drama, Dr. Devlin is faced with the intense demands of being a surgeon and working "off book" for the mafia men she once despised. As she tries to heed the demands of these two conflicting worlds, the former head of the Southside mob, Constantine Alexander, stands by her, while her boss at Roosevelt Medical and Chief of Surgery, Dr. Stafford White, and her blue-blooded boyfriend remain unaware of her "other" life, and the moral dilemma in which she finds herself in.