Sister Julienne and Doctor Turner are alive. They both lost consciousness and are in pain—Dr. Turner’s wrist may be broken and he suffered head trauma, while Sister Julienne’s ribs may be broken—but they’re alive after their train crashed into another. The door out is blocked, however, and neither of them can move much.
Dorothy Carnie, the kindly grandmother who served tea on the train and had numerous children with the Nonnatans, is in worse condition. She has been scalded by the tea and is bleeding from a cut too high on her leg for a tourniquet, so Julienne takes off her wimple to staunch the blood. Nonetheless, Dorothy dies as Julienne prays over her.
Outside the train, everyone is doing their part to deal with the tragic accident. Matthew and Miss Higgins are directing injured arrivals to Nonnatus House, which has become a first-aid post. Ambulances are prioritizing those at the site of the crash for now. The midwives are helping to treat the wounded, while Violet and Reggie are making and serving them tea. Fred is leading volunteers at the accident, and Cyril is doing whatever he can at Nonnatus House. He answers the phone when Shelagh calls: she has heard of the crash on the radio but doesn’t know of the devastation—or where Dr. Turner is.
She arrives to help at Nonnatus House, leaving Tim in charge of his younger siblings at home, and sobs in the chapel. Cyril finds her there and tells her to come aid the wounded, to be around other people and distract herself from the worry.
Nancy is similarly thrust into the fray after telling Fred that Sister Julienne and Dr. Turner are trapped on the train, and recovering with a cup of tea. She tells Sister Monica Joan the bird in Nonnatus House was a bad omen, but the nun chastises her to focus on the practical. Monica Joan indulged her curiosity in the superstitious when it was normal times, but now they all must turn their thoughts towards the present and concrete.
Miss Higgins goes to the maternity clinic to retrieve more medical supplies for Nonnatus. Sister Hilda, in the midst of attending to Edina Corbett’s protracted labor, sees her there and learns of the train crash. Edina has been waiting for her husband Lionel to arrive, but Hilda learns from Higgins that he is rumored dead: he was the conductor of the train.
Sister Hilda decides not to tell Edina until she has given birth, and asks Miss Higgins to absolutely confirm Lionel’s death. Edina gives birth to a boy—Lionel secretly hoped he would have a son—and Miss Higgins receives confirmation from the police. Edina is, of course, devastated. She will have to start a completely new life, in more ways than one.
Carole Reece’s labor was easier but tragic: the baby came too soon and couldn’t survive. Even though Carole is at the hospital, where beds must be quickly turned over, Sister Frances demands thorough, loving care for Carole in her heartbreak. The hospital midwife relents, and even lets Frances take charge of Carole’s stillbirth’s remains after Carole asks what will happen to the body. The Nonnatans have a tradition of burying a stillbirth with another deceased person, so that they can still be interred in consecrated ground, and she promises to do the same for Carole’s infant. The hospital midwife also shows kindness to Carole, putting her in a ward without other infants.
Tim is upset that he argued with his father when he saw him last. He puts his siblings in the charge of a neighbor and goes to Nonnatus with Dr. Turner’s white coat and medical bag, so that the doctor can treat the wounded. When he arrives, he learns that Dr. Turner has yet to be found, and a policeman mistakes Tim himself for a doctor, sending him to the site of the accident.
Tim wanders the wreckage calling for his father, whom Sister Julienne is desperately trying to keep awake. She hears Tim’s cries and calls out, and rescuers rush to free them from the train. Julienne has an apparent heart attack, and Tim tries to treat her, with his father’s slow-coming advice. Both patients are rushed to the hospital.
Fred reports on their condition to all the exhausted emergency respondents at Nonnatus. Normally those two tell them all what to do, so they are lost. Frances cries: Nonnatus will drown without Sister Julienne at the helm. Seeing everyone’s despondency, Miss Higgins makes a call.
Early the next morning, Nurse Crane arrives and immediately begins picking up the mess—she has cut her trip short. She chivvies everyone out of bed with a no-nonsense attitude. They can’t sleep in; they have work to do. Her efficiency helps everyone.
As everyone works to clean up Poplar, a journalist comes to Violet looking for an interview. Five people died in the accident; it’s all over the news. She has him speak to one of the many heroes of the night: Reggie.
Dr. Turner only broke his wrist; he doesn’t have a skull fracture. Tim apologizes for saying terrible things to him, but Dr. Turner jokes that his head trauma made him forget, and they reconcile. Sister Julienne is also at the hospital, which is doing tests to determine the state of her health. She is serene in her uncertainty, telling a crying Shelagh that she will probably be an invalid, and another heart attack will soon finish her off.
Frances visits Carole at the hospital and learns from her doctor that Carole seemingly had a liver problem caused by her pregnancy—hence the passing out and itchiness. It could return if she is pregnant again, but Carole has decided that she is going to focus on mothering her child Dean, not romance and boys, for now.
Dorothy Carnie’s daughter Pauline shows up at Nonnatus House and speaks to the nuns, telling them that her mother always loved the sisters. So she was glad to find a wimple—Sister Julienne’s—amongst Dorothy’s things, because it confirmed that a sister attended her as she died. Pauline wants to thank the Nonnatans for all they have done for her family—and Sister Frances has an idea of how.
She asks Pauline to allow Carole’s infant to be buried with Dorothy, and Pauline readily agrees. She gives Sister Frances a flower from a wreath at the funeral to give to Carole, who later buys her own flowers to give to Pauline in return. Carole is immediately welcomed into Pauline’s large family and invited to join them as they sit in the garden with their children.
Edina is struggling to carry on without Lionel, especially because she fears that he was responsible for the accident. She insists on going home from the maternity clinic early, so that she can provide some normalcy for her older daughter. Sister Hilda again asks Miss Higgins to gather information, and the two of them bring it to Edina together.
Miss Higgins has learned from the coroner that Lionel had a brain tumor, although he didn’t know it. It could have caused a seizure, which would lead him to lose control of the train. He is not to blame. Edina is relieved.
All of the Nonnatans and their friends are relieved when they learn that Sister Julienne is healthy: shock and injury mimicked a heart attack. Everyone joyfully welcomes her home.