In London, 1599, a man in the street serenades a woman, Lilith, in front of her home. She invites him in but when he kisses her, she becomes an ugly hag and two other hags descend upon the man, killing him.
The Doctor and Martha materialize in London, same period, and Martha is astonished at the evidence that they have traveled in time. The Doctor assures her she can’t casually change the past then suggests they go to the newly-opened Globe Theatre to enjoy one of Shakespeare’s plays. After sitting through Love’s Labours’ Lost
, they watch as Shakespeare comes out and after cheerfully berating the crowd, tells them that later that week he will be putting on a performance of Love’s Labours’ Won
. The Doctor realizes that it is one of Shakespeare’s “missing plays” that was never performed. They are unaware that Lilith is in a booth using a doll that looks like Shakespeare to briefly manipulate him.
After the performance, Shakespeare returns to his tavern where he meets with his fellows actors, who don’t believe there’s enough time to finish the play. he reassures them there is and then the Doctor and Martha burst in. Shakespeare is taken with Martha and flirts with her, but she’s not impressed. A clerk, Lynley, comes in and informs Shakespeare that since he hasn’t registered his new play the production will be shut down. Lilith, who is in the tavern, follows Lynley and dunks a doll of him in a bucket of water. Lynley’s lungs fill with water and the Doctor and Martha hear the commotion and go to investigate. Lilith kills Lynley by pounding on the doll’s heart, leaving the Doctor suspicious of the man’s inexplicable death. Lilith meets with the other two witches, Mother Bloodtide and Mother Doomfinger, and they plot together to make sure that Love’s Labours’ Won
While Martha spends an awkward night in the one-bed room with the Doctor, who is clueless as to why she’s uncomfortable, Lilith returns and first renders Shakespeare unconscious, then uses a puppet to manipulate him into writing some new lines to the end of the play. The serving girl, Dolly, interrupts and Lilith kills her. The scream attracts the Doctor who races downstairs with Martha. While the Doctor examines the girl, Martha sees the silhouette of Lilith flying away on a broomstick.
The next morning they discuss the situation and Shakespeare mentions the fact that the Globe Theatre was built by Peter Streete, who went mad after its completion, ranting about witches. The Doctor takes Martha and Shakespeare to visit the architect. At the Globe, Shakespeare’s friends stage a rehearsal and upon reciting the play’s words a brief portal opens up and a bird-like creature appears briefly. They resolve not to say anything so they don’t get locked up like Streete.
At the asylum, the Doctor manages to use his mental powers to calm Streete, who talks of the witches and gives away a street address. The witches realizes something is up and one of them goes to the asylum and kills Streete right in front of the others. The Doctor realizes that there is power in the naming of things, and connects the Globe’s fourteen-sided construction with the alien Carrionites. When he says her race’s name, the witch disappears in a burst of energy.
The Doctor explains that the Carrionites were a vicious alien race and derived their power from the mathematical structure of words. Realizing that Love’s Labours’ Won
is a weapon of words that they have created, he sends Shakespeare to the theater to stop the production while he and Martha go to the street address. Lilith is at the house and lets the Doctor and Martha in while the other witches are at the Globe and use their doll of him to knock him unconscious when he tries to stop the play.
Lilith confronts the Doctor and Martha tries to “name” her, but the words only work once. Lilith tries to kill Martha by naming her but it only knocks her out since she is out of her own time. Stating the Doctor’s name has no effect on him (since it’s only a title), Lilith boasts that her and the others of her race were trapped by the Eternals, but she and the other two were freed when Shakespeare was overcome with grief for his dead son and wrote new words that summoned them. Now they have planted the proper words in Love’s Labours’ Won
that, when spoken, will release the rest of the Carrionites so they can swarm the Earth and destroy its inhabitants. She manages to get a strand of the Doctor’s hair and attaches it to a doll (really a DNA manipulator), then hits it in the heart, seemingly killing him. She leaves and Martha wakes up, remembering the Doctor has two hearts. She manages to revive him and get his second heart going again and they head for the theatre.
The final line of the play are recited and an energy portal opens up. The Carrionites swarm out and the Doctor wakes up Shakespeare and convinces him to improvise words to send them back where they came from. A huge wind springs up, taking all the pages of Love’s Labours’ Won
with it, and sends the Carrionites back to the void. The three witches are trapped in the globe that was their power conduit, and the Doctor picks it up while the unwitting audience applauds at the amazing performance.
The next morning Shakespeare continues to flirt with Martha, who is still unimpressed. The Doctor arrives with the witches’ sphere, which he says he’ll take away in the TARDIS. Shakespeare starts to perform a sonnet for Martha but they’re interrupted when Queen Elizabeth I arrives to demand a performance. However, she recognizes the Doctor from her past (his as yet unknown future) and orders his execution. He and Martha flee to the TARDIS and make their escape.