DR. GRACE DEVLIN (Jordana Spiro, "My Boys") is a top resident at Chicago's Roosevelt Medical Center. Smart and self-assured, she's heralded as one of the country's most promising young surgeons. But family ties keep her glued to her Southside roots. To pay off her brother's life-threatening gambling debt, she makes a deal with the devil and agrees to work "off book" for the mafia men she once despised.

During the day, Grace must deal with the emotionally compelling cases at Roosevelt Medical - a toddler in need of a heart transplant, an elderly man desperate to donate a lung to his sick wife, the mass chaos in the wake of a two-train collision on the 'L.' But in her other vastly different world, she must juggle an onslaught of mob-related demands, including operating in mob-sanctioned locations, removing bullets from dead bodies to hide incriminating evidence, saving a juiced-up race horse and covertly helping an aging mobster with his erectile dysfunction.

All the while, Grace must keep her dual life a secret from everyone: her protective best friend, NURSE ROBERTA "RO" ANGELI (Floriana Lima, "Glory Daze"); her handsome, blue-blooded boyfriend, DR. BRETT ROBINSON (Zach Gilford, "Off The Map," "Friday Night Lights"); her boss at Roosevelt Medical and Chief of Surgery, DR. STAFFORD WHITE (Zeljko Ivanek, "The Event," "Damages"); her rival, DR. OLIVIA WATSON (Jaime Lee Kirchner, "Necessary Roughness," "Mercy"); even her well-meaning screw-up brother, NATE (Jesse Lee Soffer, "As the World Turns"), and her overly dramatic mother, DANIELLA (Wendy Makkena, "NCIS").

The only one who knows the true scope of Grace's activities is the man to whom Grace owes her debt: the charming and diabolical Southside mob boss CONSTANTINE ALEXANDER (William Forsythe, "Boardwalk Empire"), an oddly compassionate killer whose relationship with Grace is more than it seems. Recently released from prison, the former head of the Chicago mob looks to reclaim his place in the organization, with the help of his right-hand associate - and Grace's ex-boyfriend - FRANCO (James Carpinello, "The Good Wife").

As Grace tries to heed the demands of these two conflicting worlds - not to mention the needs of her own slightly dysfunctional family - her moral center comes into direct conflict with the very immoral things she's asked to do. But with nerves of steel and a tough-as-nails exterior, she somehow manages to make it all work - at least for now.