We meet Veronica Callahan, a very smart nurse who returns to Mercy Hospital after a year long tour of service in the Army. She's not afraid to take risks in order to save her patients, but this attitude might just cost her her job. In her personal life she's trying to make her marriage work with her high school sweetheart Mike, but when she sees the hospital new doctor it might not be that simple. Meanwhile, we meet Veronica's best friend and also nurse colleague Sonia, who thinks she finally found the man of her life and also Chloe, a rookie nurse who is learning the hard way how to be a nurse.

Veronica and her husband Mike try to rekindle their romance and move back in together, but this might not be as simple as they thought. At the hospital, Veronica and Dr.Sands try to just be friends but it's also not that easy. Meanwhile, Sonia is in love with the hunky cop Nick Valentino, who turns out to be more compatible with her than she thought. He helps her also with a Jane Doe case, while Chloe tries to help a patient everyone has already 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.

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.

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 death at the Hospital. Meanwhile, Sonia helps a beauty queen when she has to accept her life-changing diagnosis. Chloe unconvers 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 has her hands full when a group of promiscous college students is admitted to the hospital with meningitis and their love triangle has the Mercy staff comparing them to Veronica's own love life. Meanwhile, Chloe helps with wedding plans when a bride-to-be comes in with a simple flu but receives a much more serious diagnosis. Sonia has to deal with a hand transplant patient who wants his donor hand amputated after discovering it belonged to a pedophile and Dr. Sands gets a surprise visit from his sister.

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 death 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.