Angie Fulbright is pacing around her cheap apartment when her husband, Dr. Arthur Fulbright, wearily comes in. When she asks how much money he's made working, Arthur tells her to stop nagging him because he's tired. He admits that he hasn't treated anyone and Angie says that she's sick of hearing his excuses and that he's nothing. Arthur complains that he lost his nerve because of one accident, Angie reminds him that no one else knows about it. She tells him to earn a living and hints that he should go into illegal practice, but Arthur refuses. He picks up his doctor's bag and says that he'll get her some money, and staggers out.
Arthur goes to the local pawnshop and the pawnbroker welcomes him in. The doctor wants to hock his doctor's bag and the pawnbroker objects, reminding Arthur of how much good he's done in the neighborhood. Arthur doesn't see the point anymore and refuses to hear the pawnbroker say anything about Jackie, the root of his problems. The pawnbroker agrees to give him $25 but then gets an idea and offers him $20 and a black doctor's bag that someone left on his doorstep five years ago. Arthur looks at the instruments in the bag and doesn't recognize any of them, but figures that he has nothing to lose and pays the $5.
When Arthur goes home, he gives Angie the $20 and shows her the new bag. She starts complaining again but is cut off when Mrs. Colucci from next door comes in with her daughter, Maria. Maria is in a coma and Mrs. Colucci begs Arthur to examine her daughter even though she has no money. Arthur finally does so and confirms that the girl has cerebral encephalitis, and tells Mrs. Colucci that there's nothing he can do for Maria.
Mrs. Colucci begs Arthur to do something and he goes to get a sedative from his new bag so he can ease the girl's pain. Attached to the bag is used unethically, the bag will lose its curative powers and the offender will pay the full penalty of the law. Arthur finds a chart with recommended dosages but he doesn't recognize any of the drugs. Despite that, he prepares a syringe and accidentally squeezes it. Much to his and Angie's surprise, the syringe immediately refills itself. Before Arthur can figure out what's going on, Mrs. Colucci begs Arthur for help and the doctor gives Maria the injection. Much to his surprise, Maria immediately recovers and Mrs. Colucci thanks Arthur and leaves with the girl.
Once Mrs. Colucci leaves, Arthur begins to realize the power of the bag. Angie has as well and demands that the use it to make money for themselves. The couple examine the instruments and find a scalpel with a patent date on it: July 18, 2450.
Two years later, Arthur is back in private practice and examining Maria despite the fact Mrs. Colucci still can't pay. He assures her that Maria is in perfect health and has been ever since he gave her a pill last year. Mrs. Colucci thanks him and Arthur assures her that he'll always have time for her and Maria despite all of the rich patients in the waiting room. Angie comes in, working as a nurse, and brusquely tells Mrs. Colucci to leave. Arthur's wife then tells him to get busy treating their rich patients, but Arthur points out that they have enough money to last them forever. Unimpressed, Angie says that the bag's supplies could stop refilling themselves, leaving themselves destitute again.
Arthur reminds Angie about the card but she doesn't believe anyone in the 25th could do anything about it. Her husband isn't so sure, wondering if someone is monitoring how he's using the bag and making sure he isn't using it for unethical purposes. Angie pours herself a drink and takes out the scalpel, and says that she's seen it work and that it will function for anyone. Arthur warns her that training as a nurse doesn't make her qualified to conduct surgery, and says that they'll talk later about it.
The next patient is Mrs. Lagen, whose right arm is paralyzed by muscle cramps. Arthur operates on her arm, cutting into it, and immediately cures her. Mrs. Lagen can move her fingers and marvels, telling Arthur that the world should know what he can do. Arthur contemplates the scalpel and says that it will.
Once Mrs. Lagen leaves, Arthur tells Angie to send her a bill for only $50. Angie is furious but Arthur tells her that he's had enough and that he's going to turn the bag over to the AMA before something happens to him. Angie threatens to go to the police and tell them about the incident from Arthur's past: he was drunk and killed a young girl during an operation. However, Arthur says that he's no longer afraid of what he's done and that now he's going to do the right thing. When Angie tries to charm him into cooperating, Arthur tells her that it's too late and that he's already sent a letter to the AMA. Angie snatches up the scalpel and stabs Arthur in the back. As he dies, Arthur warns her that the people in the future will know.
Satisfied that she now has everything she wants, Angie figures that she can change her name and go elsewhere. However, when she opens the bag, she discovers that all of the tools have dissolved into steel wool. As the next patient knocks at the door, asking for Arthur, Angie remembers what the card said and realizes that it's all true.