At Rossillion, Bertram—the young count of Rossillion—is preparing to leave to go stay with the king of France, who will look after him since his father has recently died. His mother, the countess, is sad to see him go, and discusses the fact that the king is very ill. She mentions a famous doctor who might have been able to help heal him, but he has recently died, and left his daughter Helen under the countess’ care. Standing nearby, Helen is crying, and the countess thinks she is mourning her father. After Bertram and everyone else leaves, though, Helen reveals that she is crying because she is hopelessly in love with Bertram, who is so far above her in society that she has no hope of marrying him. Bertram’s friend Parolles enters and talks coarsely about virginity with Helen, encouraging her not to keep it for too long. After the two trade some witty quips, Parolles leaves and Helen develops a plan for trying to get Bertram.
At the king’s court in Paris, the king decides not to interfere in a dispute between the Italian cities of Florence and Siena. He will allow any noblemen who want to fight go to Italy and join the dispute, though. Bertram arrives and the king greets him, remembering his father. The king adds that he wishes he were dead like Bertram’s father, because he is so old and feeble. Back at Rossillion, the countess discusses Helen with her steward and learns that Helen loves Bertram. The countess calls for Helen and asks her if she has any feelings for Bertram. Helen confesses her love and begs the countess’ pardon. The countess does not seem to mind, and asks Helen about her plans to go to Paris. Helen says that she has some strong medicines that her father left her that she thinks can help the king, and wants to go to Paris to try to cure him. She admits, though, that her real motive for going to Paris is to see Bertram. The countess says that the king probably won’t even let Helen try to cure him, since she is only “a poor unlearned virgin,” but encourages her to go anyway.
Back at the royal court, the king bids farewell to some noblemen who are going off to fight in Italy. Bertram is upset that he is not allowed to go join the fight, because the king says he is too young. A French nobleman named Lafew asks the king if he will try any remedies for his illness, but the king refuses, having resigned himself to his own death. Lafew tells him that a young female doctor has come to help him, and the king lets her come see him, though he is skeptical. Helen tells the king that she has medicines from her famous father that could help him, but the king refuses to believe that a young girl could help him when all his doctors have failed to. Helen says that she will bet her own life that she can cure him. Impressed, the king says he will allow her to try to heal him, and will reward her with the choice of any husband from his court if she should be successful. At Rossillion, the countess orders the fool to bear a letter to Helen in Paris. After some clever joking and teasing of the countess, the fool leaves with the letter.
In Paris, Parolles, Bertram, and Lafew remark on the king’s miraculous recovery and agree that God has healed the king through the weak “minister” of Helen. The king enters with Helen and has all his noblemen line up. He tells Helen that she can choose any of them she wishes to be her husband. Helen speaks to several lords, before settling on Bertram and saying, “this is the man.” Bertram is immediately upset and doesn’t want to marry Helen. The king chastises Bertram for disliking Helen only for her lower social status, and orders Bertram to marry her. Bertram relents, and the two marry that night. Afterwards, Bertram tells Parolles that he plans to go fight in Italy and never return home to Helen. He says that he will never sleep with Helen, and Parolles and Bertram make preparations to go to Italy. Helen receives the fool’s letter from the countess, and then learns from paroles that Bertram is going to Italy and wants her to return to Rossillion. She says she will obey her husband’s command. Before Bertram leaves Paris, Lafew advises him not to trust Parolles, and says that Parolles is actually a coward and Bertram has misjudged his friend’s character. Bertram bids goodbye to Helen, and then tells Parolles that he will never see her again. The two then leave for Italy.
In Florence, the duke welcomes the French noblemen who have come to help them, and says they will go to the battlefield the next day. Back in Rossillion, the countess receives a letter from Bertram, in which he tells her that he has decided never to sleep with Helen and has run away to Italy. The countess is furious with Bertram. Helen arrives and shows the countess a letter that she has received from her husband, in which he says that he will never be her husband until she gets his ancestral ring off his finger and is pregnant with his child. The countess is upset with her son and tells Helen that she considers her a daughter. She leaves Helen alone, and Helen decides to leave Rossillion, since the only reason Bertram has no plans to return home is to avoid her, and she doesn’t want to be the cause of his being in danger in Italy. Meanwhile, in Italy, the duke of Florence puts Bertram in charge of his cavalry, and Bertram promises to devote himself to war and be a “hater of love.” In Rossillion, the countess finds a letter left by Helen that informs her that Helen has left to go on a pilgrimage to the shrine of St. Jaques, so that Bertram can return home. The countess is even angrier with her son, and writes to him so that he will come home.
In Florence, a disguised Helen runs into a widow and her daughter, named Diana. She learns that Bertram has been trying to seduce Diana, but Diana has been defending her chastity against him. Elsewhere in Florence, a group of French noblemen warn Bertram that he should not trust Parolles. They devise a plan to expose Parolles as the coward he is by sending him on a mission to recover a lost military drum. Then, they will ambush him, kidnap and blindfold him, and pretend to be the enemy. They tell Bertram that Parolles will divulge secrets and betray his allies in order to save his own life. Bertram agrees to the plan, and then goes off to try to seduce Diana. At Diana’s home, Helen reveals her true identity and promises the widow gold if she and Diana will help her with her plan. She wants Diana to pretend to give in to Bertram’s advances in return for his ancestral ring. Then, at night, Helen will take Diana’s place in her bed and sleep with Bertram in the dark. Diana and the widow agree to cooperate.
Having gone to find the drum, Parolles decides to pretend that he has tried to find it and faced the enemy by giving himself some small wounds. He is ambushed, though, by the French noblemen, who blindfold him and speak in nonsense so that he thinks they are speaking a foreign language. They tell Parolles that his life will be spared if he can give them valuable information about the Florentine forces, and Parolles says, “all the secrets of our camp I’ll show.” Elsewhere in Florence, Bertram continues to try to seduce Diana. Diana asks Bertram to give her his ring, and he resists but finally agrees to, thinking that he has won her over.
Two French noblemen discuss some recent news they have learned: Helen has apparently died on her pilgrimage, Bertram has “incurred the everlasting displeasure” of the king and the countess, and Siena and Florence have made a peace treaty. Bertram enters and the noblemen have Parolles brought in. Parolles betrays his allies and speaks ill of Bertram, trying to save his life from who he thinks are enemy soldiers. The noblemen finally remove his blindfold, and Bertram and the others desert him, planning to return to France. The next day, after Helen’s plan has been carried out successfully, she journeys with the widow and Diana to Marseilles, where they hope to find the king of France. In Rossillion, the countess and Lafew lament Helen’s supposed death. Lafew tells the countess that he has spoken to the king about Bertram possibly marrying his daughter now, and the countess says that she approves of this match. Bertram arrives at Rossillion.
Helen, the widow, and Diana arrive in Marseilles only to learn that the king has gone to Rossillion. Helen gives a letter to a gentleman to deliver to the king, before the three set out for Rossillion. Parolles arrives in Rossillion and finds Lafew. He tells Lafew what has happened to him and begs him “to bring me in some grace.” Lafew allows Parolles to enter into his service, though he calls him a knave. Having arrived in Rossillion, the king speaks with the countess and mourns the loss of Helen. He says that he has forgiven Bertram, though, and now wants Bertram to marry Lafew’s daughter. Bertram enters and apologizes to the king for deserting and dishonoring Helen. The king tells him not to dwell on the past, and informs him of the plans to marry him to Lafew’s daughter. Lafew asks Bertram for a token to give to his daughter as a gift from him, and Bertram gives him a ring that, he believes, Diana gave him in Florence (in fact it was Helen who gave it to him while they were sleeping together). The king recognizes the ring as one he gave to Helen, and questions Bertram about it. Bertram denies that the ring was Helen’s and the king calls him a liar. He wonders if Bertram had something to do with Helen’s death, and has him carried away.
The gentleman Helen met in Marseilles arrives and delivers her letter to the king. It is written by Diana and accuses Bertram of promising to marry her and then running away after taking her virginity. The king sends for Diana, and Lafew says that he will not let his daughter marry Bertram now. Bertram and Diana are brought forth, and Bertram calls Diana a liar. Diana produces Bertram’s ancestral ring as proof of his promises to her, and the countess recognizes the ring, seeing it as proof of the attachment between Diana and Bertram. Diana offers to give Bertram his ring back in exchange for hers (the ring Helen gave Bertram), and the king asks Diana how she got Helen’s ring. The king is ready to throw Diana in prison, when Helen finally enters, to the amazement of everyone who thought she was dead. Helen tells Bertram that she has fulfilled his conditions (she is bearing his child, and has gotten his ancestral ring from him), and he says that he will love her and be her husband. Realizing what has happened, the king says that Diana can choose any husband she wants from his court, as long as she is “yet a fresh uncropped flower.” He ends the play by saying, “all yet seems well, and if it end so meet, / The bitter past, more welcome is the sweet,” emphasizing how everything has apparently come to a happy end. Just after, the king comes back on the stage in a brief epilogue where he re-emphasizes that “all is well ended” and asks the audience to applaud.