The play opens in Rousillon, then a Catalan province of Spain (now in France), where young Count Bertram bids farewell to his mother the Countess and Helena, as he leaves for the court of Paris (with old Lord Lafew) at the French King's order. Bertram's father has recently died and Bertram is to be the King's ward and attendant. Helena, a young minor noblewoman and ward of the Countess, whose father (a gifted doctor) has also recently died, laments her unrequited love for (or infatuation with) Bertram, and losing him to Paris, which weighs on her though it seems to others that she mourns her father. Parolles, a cowardly military man and parasite on Bertram, trades wits with Helena, as they liken amorous love and the loss of virginity to military endeavors. Helena nearly admits her love of Bertram to Parolles before he leaves for Paris with Bertram and Lafew. Alone again, Helena convinces herself to strive for Bertram despite the odds, mentioning the King's illness alongside her decision.
In Paris, the King and noble lords discuss the Tuscan wars, where French nobles join on either side for their own glorification. Bertram, Parolles and Lafew arrive, and the King praises Bertram's father as more truly honorable, humble and egalitarian than the lords of his day or Bertram's. He welcomes Bertram as he would his own son.
In Rousillon, the Clown asks permission to marry which he and the Countess debate. The Steward explains to the Countess that he has overheard Helena lamenting her love for Bertram despite their social difference. The Countess, with sympathy and seeing Helena as her own daughter, coaxes a confession out of her. Helena admits her love, but (in decorum or strategy) reserves her previously realized ambition. They agree that Helena should travel to Paris to attempt to cure the King, even wagering her life for the opportunity.
In Paris, the King advises the Lords leaving for war, urging them to seek honor with amorous terms and warning them of the Italian women in warlike terms. Bertram, too young to go to war and in Paris to serve the King, is encouraged by Parolles and the Lords to steal away to the Tuscan war. He swears to the Lords that he will, but after they leave he admits (or reconsiders) to Parolles his intention to stay at the King's side.
Lafew asks the King to speak with Helena who offers to cure his fatal disease with her father's most potent and safeguarded recipe. The King acknowledges her late father's renown as a doctor, but refuses to entertain false hope. Through a series of arguments – showing her confidence, appealing to his irrational or mystical side, and underlining her father's reputation – she convinces the King to let heaven work through her. She accepts the King's warning that she will wager her life on the outcome, but to even the scales, she asks that she may choose her husband from the lords at court. The King agrees.
In Rousillon, the Countess sends the Clown to the Paris court with a letter for Helena, but not before the Clown teases the Countess with his impersonation of the courtiers as haughty and equivocating.
Back in Paris, Lafew tries to speak on the powers of heaven in a world of scientists, but Parolles interrupts him at every turn, trying to one-up him and claim Lafew's thoughts as his own. They bring the conversation to the King's miraculous recovery and the woman who cured him. The King and Helena enter, and the men are surprised to learn that the woman is Helena. (Lafew may be in disbelief, as he introduced Helena to the King for this purpose.) The King summons the lords and he and Helena make known their arrangement that she now choose a husband. Helena briefly questions a few of the lords, the first two of which may give perfunctory consent in front of the King, while haughtily equivocating like the Clown demonstrated previously. Helena chooses Bertram by way of giving herself to him, and the King seals her wish. Bertram balks, first asking the King to let his own eyes choose who he marries, then scorning her poverty and lack of (good) title.
The King counters Bertram's protests with offers money and title, and praises Helena variously to Bertram without his objection, but Bertram refuses again despite the King's practical beatitudes on virtue over status. The King, angered, threatens Bertram with ruin and his wrath. Bertram consents in word and the King will have them married without delay. Lafew mentions to Parolles' duty to Bertrand, and Bertram's recantation, which provoke a pique of haughty contempt from Parolles in which he disdains and threatens the old Lord. Lafew returns the animosity, and leaves and returns to announce Bertram married, and to further insult Parolles on his way through.
Bertram bemoans his fate to Parolles and plans his escape to the Tuscan wars, while sending Helena back home.
The Clown, having arrived, spars verbally with Parolles on the matter of his lack of title, duty and worth. Parolles delivers from Bertram his request that Helena take her leave of the King while Bertram attends “other business”.
Lafew tries in vain to convince Bertram of Parolles' empty viciousness. Bertram won't hear of it, and Lafew asks Bertram to mend relations between him and Parolles, likely sarcastically, since as soon as Parolles enters, Lafew subtly works toward a full indictment of Parolles as nothing but a shell of a man with a good suit on. Bertram tells Helena that he has urgent business to attend to as their surprise wedding has left him with unsettled matters, and that he will arrive at home in two days. She finds the courage to ask him for a farewell kiss, which he refuses.
In Florence, the local Duke and the French Lords discuss the King of France's abstention from the Tuscan war, and the Duke welcomes the participation of the many French lords who have come to seek honor and glory.
In Rousillon, the Clown informs the Countess of the marriage of Bertram and Helena, as well as Bertram's melancholy, adding that Clown has lost interest in the woman he wanted to marry after seeing the Parisian court's version of her. The Countess reads Bertram's letter, disapproving of his flight to Florence, and the Clown rattles off equivoques on cowardice in war and marriage.
Helena and the Lords returned from Florence enter to elaborate on Bertram's flight. Helena, dejected, reads Bertram's sardonic letter claiming that she'll have him as a husband once she gets his family ring and has his child. The Countess disavows him and claims Helena as her own daughter, giving the Lords this message of disapproval to take to Bertram. Helena, alone and hoping to give Bertram cause to return from the dangers of war, plans to disappear from Rousillon in the night.
In Florence, the Duke makes Bertram his cavalry officer.
In Rousillon, the Countess reads Helena's farewell letter, declaring her pilgrimage to Saint Jaques (putatively in Spain, or at least not in Florence or Rousillon). The Countess sends word of this to Bertram, hoping he'll return from Florence now that Helena is away.
In Florence, a Widow, her daughter Diana, Mariana and other women speak of the soldiers and watch or wait for them from afar. They discuss Bertram's success in war and his and Parolles' seduction of the local virgins. Helena arrives disguised as a pilgrim, who are hosted in Florence at the widow's house. She hears of Bertram's martial fame, his history, and his most recent attempts to seduce Diana, with more equivoques between war and the seduction of virgins. Helena befriends the women.
The Lords warn Bertram of Parolles' dishonorable behavior, staking their reputations with Bertram on its veracity. Bertram, now more receptive to the possibility, agrees with the Lords' scheme to send Parolles off to recover his drum, lost in the day's battle, so that on his return, they can capture him disguised as the enemy. Parolles enters to take the bait, and affecting pride, swears to recover it. Bertram takes a Lord to show him Diana.
Helena has identified herself to the Widow, a fallen estate noble, and enlisted her help for coin in order to get Bertram's family ring and switch Diana for Helena in a bed trick.
A French Lord and his soldiers lie in wait for Parolles, who bides his time and wonders how long of a story and how many self-inflicted injuries will satisfy the others when he doesn't return with a drum. The disguised French ambush him, and he immediately panics and offers information on the Florentine cause.
At the Widow's house, Bertram attempts to woo Diana who questions his motives and sincerity. Once Bertram attests that he is eternally sincere, and guileless, Diana plies him for the ring, offering to trade it for a ring (from Helena) and her virginity. Bertram accepts.
The Lords discuss Bertram's letter from his mother expressing her disapproval, how it negatively affects him, his caddish behavior, and the recently received rumor of Helena's death at Saint Jacques. Bertram enters, having arranged his affairs for departure no sooner than having heard of Helena's death. The Lords, hoping he see the error of his ways through Parolles' unmasking, take him to the blindfolded Parolles, who readily offers martial information on Florence to save himself with hardly a provocation, as before. He is equally forthwith in besmirching Bertram's character to the "enemy" on discovery of a note to Diana, advising her to leech money from Bertram as he tries to seduce her since he will betray her afterward (ostensibly written to her in an undelivered compact to bilk Bertram of gold). They reveal themselves and shame Parolles into near-silence. Alone and humbled, he concludes to follow them back to France.
Helena, the Widow and Diana discuss their success (the seduction having happened offstage) and Helena muses on the love-hate of Bertram, (or tricked-seducers of his kind, or men in general) during the sexual act. She asks the Widow and Diana to accompany her to the King in order to complete her winning or cornering of Bertram.
In Rousillon, the Countess, Lafew and the Clown mourn the loss of Helena. Lafew has proposed to the King that Bertram marry his daughter, which meets with the Countess' approval.
In Marseilles, Helena, the Widow and Diana send a Gentleman ahead of them to Roussillon with a letter to the King concerning Bertram.
In Rousillon, Parolles, now a reeking beggar, begs for help from Lafew, who allows him in for supper.
The King, Lafew and the Countess mourn the loss of Helena and decide to forgive Bertram's foolish young pride. Lafew and Bertram have arranged his marriage to Lafew's daughter, and the King consents. Bertram enters, asking forgiveness, and expanding on his love for Lafew's daughter, whom he loved at first sight. This love provoked his disdain for Helena, whom he belatedly appreciates.
Lafew, whose estate will pass to Bertram in the marriage, asks for a ring from Bertram to give to his daughter. Bertram gives him the ring from Diana (which came from Helena). The King, Lafew and the Countess recognize it as the ring that the King gave to Helena, which Bertram denies. The King has him seized, suspecting foul play (the King knows that she would only surrender it to Bertram in their bed, and Bertram believes that this is an impossibility). The Gentleman arrives, giving the letter from Diana and Helena to the King, in which it is claimed that Bertram pledged to marry Diana as soon as Helena has died. Lafew rescinds his daughter's hand.
Diana and the Widow enter and Bertram agrees he knows them, but not that he seduced her or promised her marriage, claiming she is a Florentine harlot. Diana shows Bertram's family ring, and claims Parolles as witness to Bertram's efforts to woo her. Bertram changes his story, claiming to have foolishly given her the ring as over-payment for her harlotry. Diana further claims Helena's ring, as recognized by the court, as the one she gave Bertram in bed. With the confusion reaching a peak, Parolles, once pressed, admits that Bertram seduced and bedded her, and Diana equivocates over how she got Helena's ring. The King order her arrest as well, and she then summons the Widow and Helena.
After the court's shock, Helena explains the rings, and that she has fulfilled the conditions of Bertram's sardonic challenge. Bertram swears to love her if she has honestly done all of this and can explain it. Helena pledges honesty, or righteous divorce for Bertram. Lafew accepts Parolles as a servant. The King offers Diana a dowry and her choice of husband.
The play ends as the actor playing the King steps forward in epilogue, declaring that all is well if Helena and Bertram speak truthfully, and asks for the audience's approval.
