Dr. Luisa Delgado is fighting to keep her South Philadelphia women's free clinic open by herself. Lu decides to go to Rittenhouse Hospital ask for some financial help. However, it turns out that Dr. Dana Stowe blames Lu for ruining her breast cancer study. Chief of Staff Dr. Bob Jackson tells Dana to take a tour of the clinic to see if Rittenhouse should help fund it. In the meantime, Dana has to tell one of her patients that her sister might be at risk for ovarian cancer as well and tries to convince her to tell her sister that she needs to remove her ovaries and her chances of having children.
Lu and Dana are finding it difficult to work together in their new joint practice. Dana has to tell a surrogate couple that their baby is going to born with severe mental birth defects. They begin to wonder if they can handle taking care of child with such needs. Meanwhile, Lu has to investigate a clinic that supposedly gave a woman a hysterectomy because of bleeding fibroids, but it turns out they never gave her one.
Lu and Dana wind up clashing over a woman who has AIDS and the way she chooses to treat her child. After Dana treats the woman who has taken her HIV-Positive son off his medication because it makes him violently sick, she reports her to the Chief of Staff. Lu reveals that she told the mother it was okay to take him off the medication, but Bob requires the drugs be re-administered to him. Meanwhile, Dana gets a visit from a talk show host under the pretense of doing a story on artificial insemination and Peter makes a house call that does not go as planned.
Dana is shocked when a former beauty queen asks her to perform a surgery on her that she thinks will make her husband believe she is more beautiful. Lu overreacts when she accuses a former drug addict of using again, when in reality she has a very chronic and dangerous condition. Peter cannot understand why a transvestite is having side effects of menopause and also counsels Marc about one of the issues of male adolescence. Meanwhile, Lu and Lana try to find a way to punish two girls who sprayed graffiti on the exterior of the clinic.
After a basketball player passes out, Lu quickly discovers it is not only talent that it causing the young girl to perform so well. The test reveals steroids and Lu wonders if the entire team is on the drugs. Dana is surprised when a woman who was beaten unconscious, has shown up in the ER with her name and phone number in her pocket because she has never met her before. Soon Dana must perform a major surgery on the woman, but has no family to get permission from.
The clinic benefactor Dr. Lydia Emerson drops by at a time when both Lu and Dana have their hands full. Lu is trying to deal with her son's mugging at school, plus a group of drug-addicted prostitutes who all want their tubes tied for money. Meanwhile, Dana is shocked when Susan Jackson comes into the ER with bruises and wonders if Robert gave them to her. After finding out from Robert that he found Susan at the bottom of the stairs and that she had some double vision, she begins to wonder if Susan is suffering from Multiple Sclerosis.
Lu, Dana, and their patients end up caught in the middle of a gang fight. The gang members have become frustrated because they cannot get health insurance and feel that the councilwoman that Dana is treating might be able to help them. When she says no, one of the lashes out and shoots her. Peter uses acupuncture and hypnotherapy to ease the chronic joint pain of a middle-age mother but soon discovers what the real source of all her pain is.
Dana is conflicted after she treats a commercial pilot and discovers that she has a degenerative brain disease. She does not know whether she should break doctor/patient privilege to prevent her from flying another plane. Also, a soon-to-be-engaged man and woman find themselves joined at the hip before either him have a chance to tie the not. Finally, two Catholic parents have to question their faith and their families when Lu discovers their baby girl has Tay-Sachs which is a genetic disorder normally found in people of Jewish descent.
Dana has to go underground when she decides to help the wife of a high-powered real estate developer whose has been abusing her. Meanwhile, Lu has to come between an orphaned boy with attention deficit disorder and his foster guardian when she discovers that the Ritalin she prescribed him is being used by her instead. Lu also ends up finding a love connection in a very strange place.
It's Breast Cancer Awareness Weekend at the Rittenhouse Hospital Women's Clinic and Lu, Lana and Peter are hosting a dance-a-thon and a free mammogram clinic. After one woman's mammogram reveals a lump, Lu tries to intervene to help her keep both her breast and her job. Meanwhile, Dana discovers some unexpected results of her breast cancer clinical trial and soon learns the very disease that's defined her career has now hit too close to home.
Dana decides that she will take a leave of absence from the clinic so she can help her mother through her double mastectomy. Meanwhile, the impromptu safe-sex speech that Lu gives at a prep school's career day ends up putting her in the middle of a legal dispute over a date rape. Peter's approach to pain management for a patient with Hodgkin's disease ends up getting them both arrested. Also, Dana and Lu must each decide how much they want to know about their genetics when they both decide to test for the mutated BRCA1 and BRCA2 genes that would reveal if they are a candidate for breast cancer.
Dana and Robert to decide whether to perform a controversial cell transplant, after a woman's Parkinson's Disease continues to worsen. Lu ends up treating one of her son Marc's classmates for a broken wrist and discovers that alcohol may have been involved the junior high school student's accident. Peter's job as a nude model leads to some romance with an aspiring painter whose muse puts her in the emergency room.
Lu and Dana becomes upset and decide to help when a woman with a controversial bone and muscle disease is denied her disability claim and thus has no insurance coverage. Dana ends up getting in the middle of an immigration dispute when she finds out that the physical damage on a 15 year-old sexual assault victim was actually inflicted by the girl's parents as the result of a cultural ritual.
A soon-to-be mother and father struggle over whether to let Dana perform an in-utero procedure that will correct a birth defect for their son. Lu has to decide if she wants to get involved in the case of a woman who she diagnosed with schizophrenia and is now charged with murder.
Christmas arrives at Rittenhouse and so do the odd stories. A newly engaged woman discovers she's pregnant, but she has never had intercourse. Robert fires a kitchen employee after he thinks that she is drunk on her job, but Lu finds out something else about her. Meanwhile, Mark finds himself with a crush on a runaway girl.
A respected journalist, who is also a heroin addict, comes to Dana for a clean supply of needles. Lu tries to get a deaf mother and her child to obtain hearing implants, but her husband disapproves of the surgeries. Meanwhile, Mark finally meets Lu's new boyfriend.
A 25 year old women enters Rittenhouse with symptoms that suggest early menopause. It's soon discover that environmental toxins in her housing complex have caused the disorder. Also, a new mother cannot handle the pressure and runs away from home and leaves her baby behind. Meanwhile, Dana finally gets the chance to meet Nick's mother.
After a 12 year old girl complains of a sore throat, test reveal that she actually has oral gonorrhea. The girl then reveals who she got it from - her teacher. Lana ends up taking a new role at Rittenhouse, one she would rather not have, that of patient. Meanwhile, two of Dana's patients deliver babies on the same day and both of the babies have the same father.
Dana has a huge dilemma when one of her patients, who is also a video game creator, begins to lose her battle with cystic fibrosis. Her mother says she told her she wanted to live, but her husband says otherwise and he wants her off the life support. Lu encounters a mother who wants her to give her some medication that will allow her autistic daughter to speak.
Dana has to care for a dying patient that she thought was a man, until she discovers the woman was disguising herself to fulfill her dream of becoming a priest. Lu decides to prescribe Demerol to a woman who is suffering from sickle cell anemia, but the woman's local pharmacy will not carry the drug because they are afraid they will be robbed for it.
Lu has to work an all-nighter at Rittenhouse and encounters some strange stories. One of them includes a newborn baby that is stolen from it's mother's womb. Robert's wife, Susan, is admitted to the hospital as her MS continues to get worse. Also, Lana's blind date ends up in the ER himself.
A mother decides to go on a hunger strike to try and save her son from his impending execution. Meanwhile, Dana considers leaving Rittenhouse after something devastating happens while she is in the OR.
When a young mother cannot find a suitable heart donor, her husband decides to take matters into his own hands. Dana and Lu fight about whether or not an Ivy League student should sell her eggs to a couple who cannot have their own children. Meanwhile, Nick wonders if he will get named to the ER staff or not.
One of Lu's patients sues Robert for "fat discrimination" after he refuses to hire her for his new secretary. Dana treats a military officer for Gulf War Syndrome and the Army is not to pleased with the diagnosis. Lana thinks about adopting a young infant who was abandoned by his mother at Rittenhouse.
An overworked nurse at Rittenhouse sues the hospital after she is pricked with an AIDS-infected needle while in the ER. Dana has to remove a tumor from the brain of a woman she went to high school with, who also happened to hate her. In the meantime, Dana and Nick end up having their very first fight.
Lu goes to Puerto Rico to help her grandmother who is dying try and get a bone marrow transplant and soon discovers that her grandmother has been harboring a secret for years. Meanwhile, through flashbacks, it is revealed how Lu, Peter, and Lana all met and became who they are today.
Robert decides to use Rittenhouse's Ethics committee after the parents of Siamese twins refuse to separate the two little girls. Lu wonders if her leukemia patient, who is a firefighter, is really a hero or not after she discovers something about the woman after she saves two homeless people. Meanwhile, Peter thinks a woman might have a severe virus after she shows up with a strange rash on her arm and Lana is put in charge of Rittenhouse's new Safety and Emergency Plan.
Dana has the entire city of Philadelphia mad at her after she ends up calling away the Phillie's star pitcher during a major play-off game when his wife goes into labor. Lu treats a piano prodigy who has scleroderma and it has begun hardening her hands so she can no longer play. Meanwhile, Peter spends his time trying to save a now retired research chimpanzee from execution.
Dylan struggles with fatherhood and dating; Lu can't figure out why her 11 year old patient is constantly gaining weight.
Lu and Jonah's wedding day finally arrives, but not without complications; Meanwhile at Rittenhouse, Dylan is busy with a woman about to deliver twins and finds out his daughter has been arrested.
Dylan tries to get a transplant for a Down Syndrome patient; Lu finds out that several of her patients have had unprotected sex with an AIDS-infected man as a part of a gang initiation, as the staff wonders what is wrong with Lu's mood lately.
While Dylan is trying to save the life of the governor, Lu is actively pursuing her regarding a patient who is on death row. Meanwhile, Kayla seeks Dylan's advice as she treats a young pianist whose left hand has been severed. And weary from dealing with overwhelmed teen mothers, Peter starts a boot camp for teenage fathers. With Jonas out of the country trying to save his business, a pregnant and anxious Lu calls on the other two men in her life — Dylan and Peter — for moral support.
Lu must crack a puzzling mystery when her patient is accused of welfare fraud because her children's DNA doesn't match her own. On a personal front, the doc's life is equally stressful as she and Jonas find out that something might be wrong with their baby. Meanwhile, Peter makes a surprising discovery when he attempts to heal his injured shoulder with herbal remedies.
A 16-year-old girl is supposed to donate a kidney to her older sister, but she pleads with Lu to stop the lifesaving surgery. Having spent most of her life donating blood and bone marrow to her sibling, who suffers from leukemia, the teen can't bear any more procedures. The parents are furious, and Lu is caught in the middle of this family drama. But when the adolescent downs a bunch of pills, her older sister decides to call off the procedure anyway. Meanwhile, Kayla and George compete for the position of chief resident. Despite rumors that affirmative action was involved, Kayla gets the coveted job based solely on her merits.
When an out-of-state insurance company mandates that Dylan's patient be released less than 24 hours after having a mastectomy, he finds a way to get around the system in order to give this woman the proper care. Meanwhile, Lu's cerebral palsy patient decides to take legal action against her mother, who had smoked the entire time she was pregnant with her. And new dad Dylan enlists Lu's help in talking to his own daughter about quitting smoking and how he should approach the teen on the delicate subject of sex.
Lu works feverishly to save two patients in the burn unit, one a firefighter and the other an ugly duckling who has an adverse reaction to medication that's causing her skin to fall off. The pair is separated by a curtain but continue to talk and offer each other support; eventually they fall in love. Meanwhile, Kayla and Peter clash in the ER over how to handle the death of a teenage boy who died from heart failure. Eventually, they see eye to eye and work with the deceased's family to raise funds for the adolescent's deadly but detectable condition (hypertrophic cardiomyopathy).
Christmas at Rittenhouse finds Lu not only taking care of her own heavy caseload, but also treating Dylan's patients while he spends the holidays away with Araya. Lu's main priority is finding a home for three siblings who were abandoned by their meth-addicted mother. Meanwhile, a Santa with a Scrooge-like attitude visits the hospital.
When Lu's patient's appendix ruptures, she looks to Dylan to help her save the woman's fertility. Kayla tries to make amends with her estranged twin sister Keisha, but after she becomes unreasonably belligerent, Kayla begins to worry something more than sibling rivalry is troubling her.
Lu tackles a rare and deadly disease that does not respond to conventional treatment. Lu circumvents the insurance system for a far less conventional but much more effective medication. Dylan uses his faith to try and convince his patient to fight for her life.
Lu struggles to help a seriously ill pregnant woman without hurting her baby. Kayla pretends that a patient is alive to appease his unstable girlfriend, who says she has a bomb. Meanwhile, Peter looks for a missing boy, and Lana soothes an elderly man about to enter a nursing home.
Lu and Dylan are forced to confront an ethical dilemma when they begin using an experimental drug on a patient. Also, Dylan faces losing Araya to her maternal grandparents, who come to town hoping to make a fresh start with the teen and ask her to make a huge life decision.
In the series finale, Lu is forced to have a special delivery after she is trapped in a basement. With her medical guidance, Lu's husband, Jonas, performs an emergency c-section. Dylan struggles to save a gunshot patient who tells him the name of the gang member who shot her. After going to the police, Dylan realizes he may have put his family in danger