Nurse Veronica Callahan has just returned to Mercy Hospital after a tour of duty in Iraq. Though not afraid to bend the rules in order to save a life, her outspoken attitude might cause her to lose her job. While trying to get over her broken marriage to Mike, she catches the eye of the newest doctor, Dr. Chris Sands. Meanwhile, Sonia, Veronica's best friend, thinks she may have found the one; and rookie nurse Chloe learns the hard way what it means to be a nurse.

Veronica and Mike try to put the pieces of their marriage back together, but after deciding to move in together they realize their house needs more work than their marriage. At the hospital, Veronica has a hard time staying just friends with Dr. Sands; Sonia has Nick Valentino help her identify a Jane Doe; and Chloe helps a patient everyone else has given up on.

The hospital is at crisis, and Veronica tries to save the only survivor of a nightclub fire. The patience then has to go to therapy for the guilt he feels and Veronica realizes that she could also use some therapy herself. Meanwhile, Chloe wants the respect of her coworkers therefore she changes to a more mature wardrobe and attitude. Also, Sonia butts heads with a new doctor, while the nurses see Dr. Harris romantically interested in a mysterious beauty.

Veronica, tries to decide if the affair with Dr. Sands is really in the past, because Mike wants to start a family with her. And, while helping a veteran get treatment, Veronica's own issues from Iraq surface. On the other hand, Sonia experience the good and the bad from dating a cop, while she has to deal with a fight between two patients who are in a love-hate relationship. Meanwhile, Chloe gives hope to a young cynical patient while thinking of taking her crush on Dr. Sands to the next level.

After Veronica announces she's trying to get pregnant, to her surprise a pregnant woman and her unborn child need her help after a horrible car crash. Meanwhile, Dr. Harris, calls a meeting to determine Veronica's future at Mercy. Sonia helps a sleepwalking patient and her relationship with Valentino deepens, while Chloe goes on an ambulance and makes a discovery that will change Dr. Harris life forever.

As her affair with Dr. Sands surfaces, Veronica contemplates to come clean to her husband. Sonia gets relationship advice from a patient and questions her approach to dating, just as her boyfriend goes missing. Meanwhile, Chloe reunites with an ex-boyfriend but her plans take an unexpected turn when she learns some news.

After Veronica's affair becomes public, she and Mike reunite in a family crisis from Veronica's side. Meanwhile, Sonia is agitated when her high school rival comes to the hospital and ends up being her patient. Only to discover that the life of her rival life is not as perfect as she though. Later, things heat up between Chloe and her fireman, while Dr. Sands moves on from Veronica to another Mercy staffer.

Veronica might be pregnant but worries that maybe not even a baby can save her marriage. She needs to regain control of her life, and decides to work with Dr. Harris against any passing at the Hospital. Meanwhile, Sonia helps a beauty queen when she has to accept her life-changing diagnosis. Chloe uncovers a secret her boyfriend has been keeping from her, while Dr. Sands gets more close to Dr. Jelani while organizing a "Bike to Work Friday" activity.

Veronica turns to a vetrans support group for help with her Post Traumatic stress, while struggling with her fathers rapidly deteriorating mental health. While chloe is forced to treat her most diffucult patient after Dr Harris suffers a mysterious injury.

Veronica helps a patient after a terrifying experience on an operating table. Meanwhile, Veronica begins to think that Mike has begun dating again. Sonio tries to find a patient's next of kin, but instead comes across a secret that will change the young girl's life forever. Elsewhere, Chloe is forced to moderate a family feud when a family can't agree on the course of action for their dying father.

Veronica has her hands full when a trio of promiscuous college students is admitted with meningitis and their soapy love triangle has the entire Mercy staff drawing comparisons to Veronica's own complicated love life. Meanwhile, Chloe helps with wedding plans when a bride-to-be comes in with the flu and receives a much more serious diagnosis. Sonia manages a defiant hand transplant patient who wants his donor hand amputated after discovering it once belonged to a pedophile and Dr. Sands gets a surprise visit from his freewheeling sister.

A newlywed cancer patient is in a risky treatment and Chloe struggles to help her husband. Meanwhile, a man wakes up after tn years in a coma and he decides to confront the love of his life, helping Veronica to take action in her own love life. Meanwhile, Sonia gets a taste of how rich people live when she has a wealthy and eccentric patient to care for.

Dr. Joe Briggs, the new head of ICU arrives at Mercy. While, Veronica and Dr. Sands must set aside their problems to save a boy found nearly frozen in the woods. After the passing of one of her patients, Chloe tries to help the grieving widower leave the hospital and Sonia continues her turn as a private nurse to an upper-crust family.

Veronica is trilled to be back with Dr. Sands but their first official date is ruined by a robbery. Meanwhile, Chloe and Guillermo are put to the test in the fast-paced, high-stakes world of the ER after being re-assigned there by the arrogant new head of ICU. While Sonia bonds with the son of the rich elderly patient, and she begins to question the lifestyle she has settled into with Valentino.

Following the donut shop shooting, Veronica finds herself overwhelmed by PTSD. Accompanied by a disturbing visitor, she takes off on an impromptu road trip, leaving everyone concerned. Back at Mercy, the victims of a bus bombing inundate the E.R., causing Dr. Briggs and Dr. Sands to clash over the only available operating room. Chloe battles a hangover on her second day in the E.R., Sonia struggles to conceal her infidelity from Valentino and Dr. Harris treats a patient whose injury causes her to make inappropriate sexual advances.

Veronica takes on extra shifts and rekindles her relationship with Dr. Sands in an effort to avoid dealing with her recurrent PTSD symptoms triggered by the robbery. But when she makes a terrible discovery about a young patient, her impulsive reaction shocks everyone - including her. Meanwhile, Sonia is confronted with an agonizing ethical decision when her elderly home-care patient announces her plan to end her own life, and Chloe gets the surprise of her life when she accompanies Briggs on a VIP house call.

Veronica cares for an anorexic patient who is almost as good at denial as she is. When Sands and the Flanagan clan confront Veronica after a St. Patrick's Day binge, she considers seeing a therapist. After working with him to save a heart attack patient, Chloe softens slightly toward the arrogant Dr. Briggs when she learns why he became a doctor. Meanwhile, Sonia, still privately mourning the passing of her home-care patient, is surprised to run into her ex-boyfriend at a St. Patrick's Day fair.

Veronica begins the difficult process of confronting her PTSD with her therapist. Although Sands is eager to move forward with their relationship, Veronica finds herself siding with Briggs against him in a dispute over a patients treatment. Chloe and Harris team up to help a cute college football player with a potential brain injury and Angel butts heads with an eccentric ER patient. Meanwhile, Sonia cares for two hipsters after their hair-brained attempt to win a girls heart lands them in the hospital, but their romantic gesture inspires her to make her own.

Veronica experience a panic attack and resumes her PTSD therapy with Dr. Cabe. Chloe and a frat boy admirer hunt down a patient with a potential fatal problem. Meanwhile, an unforseen autopsy of the home-care patient of Sonia can put her in danger

After a prison riot, several prisoners are brought to Mercy. Veronica sympathizes with her patient but is chocked to discover a secret he's been keeping. Chloe tries to convince her boyfriends to treat his head injury before it's too late. And, when Sonia's tough patient admits that he's terrified to go back to prison, she worries that she can end in prison too. Meanwhile, Briggs has to make a choice that could destroy his career or his life.

When one of Veronica and Sand's friends from Iraq show up unexpectedly and they have to make a life or passing decision. Sonia gets help from a surprising source, when she has a stalker after her. Chloe worries that her boyfriend is damaging her brain by playing football against medical advice.

When one of Veronica and Sand's friends from Iraq show up unexpectedly and they have to make a life or passing decision. Sonia gets help from a surprising source, when she has a stalker after her. Chloe worries that her boyfriend is damaging her brain by playing football against medical advice.