A class of interns arrives for their first year in training at a public city hospital, which serves patients from many different ethnic and socioeconomic groups. Close friends and classmates John Paul Otis (Robertson) and Lew Worship (James MacArthur) plan to become surgeons and open their own clinic together. They are less than thrilled about their assignment to obstetrics, feeling that delivering babies is not very difficult.
Lew becomes romantically involved with student nurse Gloria (Stefanie Powers), while John becomes infatuated with fashion model Lisa Cardigan (Suzy Parker). Lisa dislikes the idea of dating a relatively impoverished young doctor, and is pregnant out of wedlock by another man. Although John offers to solve her problem by marrying her, she pressures him to illegally obtain pills for her in hopes of ending the pregnancy. He finally does so, and is caught and reported by Lew, ending their friendship and John's medical career.
Sid Lackland (Nick Adams) aspires to serve wealthy patients so he can make a lot of money. Then he becomes attached to Loara (Ellen Davalos), a girl from a poor village in Southeast Asia, who is one of his patients. She has a rare medical condition and is scheduled for a serious operation. Loara resists his friendly overtures because she is sure she will die in the hospital. Sid is heartbroken when Loara dies during her surgery.
Alec Considine (Callan) wants a residency under eminent psychiatrist Dr. Bonney, and secretly cheats on his wealthy fiancee Mildred (Anne Helm) with Dr. Bonney's longtime nurse Vicky Flynn in hopes of being introduced to the doctor. To keep up his medical duties and spend time with both women, Alec takes Dexedrine to stay awake. Although he does meet Dr. Bonney, who offers him a residency, Mildred discovers his affair and leaves him.
Madolyn Bruckner (Haya Harareet) aspires to become a surgeon under abrasive Dr. Domenic Riccio (Savalas). Despite her skills as an intern, Riccio discourages her because he is prejudiced against female doctors, assuming they will abandon their medical careers to get married and have children. Riccio later finds out Madolyn has already been married and has a child, yet is still pursuing her medical career as a single working mother.
At the end of the year, Alec, Lew, and several other interns come under suspicion when a terminally ill, immobile patient who has been begging to die is found dead of a barbiturate overdose. None of the involved interns can accept their residencies until the source of the drugs is found, creating a risk that the residency offers will be withdrawn. Alec, strung out on Dexedrine, has a nervous breakdown at the thought of losing his residency with Dr. Bonney. Lew and the other interns visit the patient's wife and find out that she gave him the drugs after being worn down by his constant pleas that if she really loved him, she would help him die. As a result, the interns are no longer under suspicion and can accept their offers.
Lew, having developed an interest in obstetrics after delivering a baby, accepts a residency at the same hospital, and convinces Gloria, who had planned to travel and see the world, to marry him, instead. Sid gets an offer from a wealthy hospital, but inspired by Loara, he goes to practice in impoverished Southeast Asia, instead. Riccio hires Madolyn as his resident assistant. John, now engaged to Lisa, visits his former classmates and tells Lew he respects him for his sense of ethics. A new class of interns arrives and Lew shows them the way to their dormitory, just as a doctor did for him the previous year.Michael Callan as Dr. Alec ConsidineCliff Robertson as Dr. John Paul OtisJames MacArthur as Dr. Lew WorshipNick Adams as Dr. Sid LacklandSuzy Parker as Lisa CardiganHaya Harareet as Dr. Madolyn BrucknerStefanie Powers as GloriaAnne Helm as MildredBuddy Ebsen as Dr. Sidney WohlTelly Savalas as Dr. Dominic RiccioKaye Stevens as Nurse Didi LoomisEllen Davalos as LoaraAngela Clarke as Mrs. Emma AuerConnie Gilchrist as Nurse Connie DeanKatharine Bard as Nurse Vicky Flynn
The film was based on a novel by 26-year-old Richard Frede, who had worked as an intern for two years. It was published in 1960 and became a best seller. Film rights were bought for a reported $75,000 plus 15% of the profits. It was optioned by producer Robert Cohn who set up the project at Columbia.
Robert Wagner had signed a three picture deal with Columbia, and announced he would play the role of Lew. "This won't be another Dr. Kildare picture, with the standard romance and the other stereotypes, I can assure you," said Wagner. However his role ended up being played by James MacArthur.
Sidney Poitier was also announced for the cast but did not appear in the final film.
The movie originally ran for three hours but was cut down to two.
The film grossed $9,230,769 at the box office, earning $5 million in US theatrical rentals. It was the 12th highest grossing film of 1962 and Columbia's biggest grossing film of the year.