A young woman is serenaded from her balcony by a lute-playing suitor, Wiggins. She bids him enter the house, but to his
shock he finds it full of witching artefacts. The woman, Lilith, kisses Wiggins — but, on pulling away, he finds her
transformed into a wrinkled hag. She introduces her two "mothers", Doomfinger and Bloodtide, who appear, cackling, and lunge
at the screaming youth, apparently devouring him.
Meanwhile, the TARDIS lands in Elizabethan London. Martha questions whether it is safe to walk around in the past, citing
such time travel concepts as the Grandfather paradox and a reference to the Ray Bradbury short story "A Sound of Thunder";
and also worrying about her reception as a black woman in a time when slavery still exists. The Doctor tells her not to worry.
He declares that they have arrived in London in 1599 and takes her to a performance at the Globe Theatre. At the end of the
play, Love's Labour's Lost, Shakespeare announces that there will soon be a sequel called Love's Labour's Won.
Lilith, using a poppet, influences Shakespeare to declare, rashly, that the new play will premiere the following evening.
Martha asks why she has never heard of Love's Labour's Won. The Doctor knows of the lost play and, curious, decides
to find out more about why it was never published — and extends Martha's "one trip".
The two go to The Elephant, the inn where William Shakespeare is staying. They chat with the playwright, who intends to
finish writing the final scene of Love Labour's Won that night. An instantly beguiled Shakespeare ("Hey nonny nonny!")
tries to woo Martha, describing her as "a queen of Afric" or a "Blackamoor lady", which she finds slightly offensive. The
Doctor claims she comes from 'Freedonia' to explain her strange clothing and modern attitudes. Shakespeare sees past the Doctor's
psychic paper, which the Doctor cites as proof of the man's genius.
Lynley, Master of the Revels, demands to see the script before he allows the play to proceed. When Shakespeare offers to
show him the finished script in the morning, the official leaves proclaiming that this slight means he will ensure the play
will never be performed. The trio of 'witches' watch the scene in a cauldron. Lilith, who works at the inn, secretly takes
some of Lynley's hair and makes another poppet, which she plunges into a bucket of water. The Doctor, Martha and Shakespeare
hear a commotion in the street and run out, where they witness Lynley vomiting water. Lilith stabs the doll in the chest,
and Lynley collapses, dead. The Doctor calmly announces that Lynley has died of an imbalance of the humours, and privately
tells Martha that any other explanation would lead to panic about witchcraft. When Martha asks what did kill Lynley, the Doctor
Martha and the Doctor stay overnight at the inn. The Doctor gives a disgruntled Martha mixed signals by casually sharing
a bed with her only to then openly bemoan the lack of Rose's insight. Meanwhile, Lilith entrances Shakespeare and, using a
marionette, compels him to write a strange concluding paragraph to Love's Labour's Won. She is discovered by the landlady
(also the Bard's lover), whom she frightens to death. On hearing another scream, the Doctor runs in and finds the body. Through
the window, Martha sees a witch fly away on a broomstick.
In the morning the Doctor, Martha and Shakespeare proceed to the Globe Theatre, where the Doctor asks why the theatre has
14 sides. Shakespeare replies that the architect thought it would make sound carry well and mentions that he eventually went
mad and talked of witches. The three then visit the architect, Peter Streete, in Bedlam Asylum. The Doctor helps Streete to
emerge from his catatonia for long enough to reveal that the witches dictated the Globe's design to him. He also tells the
Doctor that the witches were based in All Hallows Street.
The witches observe this interview through their cauldron. Doomfinger teleports to the cell and kills Peter with a touch.
She threatens the other three but the Doctor works out who the 'witches' really are. He names the creature as a Carrionite,
which causes her to disappear. The Doctor explains that the Carrionites produce their "magic" through an ancient science based
on the power of words.
Back at the Elephant, the Doctor deduces that the Carrionites intend to use the words of a genius — Shakespeare —
to break their species out of eternal imprisonment when Love's Labours Won is performed. The Doctor tells Shakespeare
to stop the play whilst he and Martha go to All Hallows Street to thwart the witches. Shakespeare bursts on to the Globe's
stage to make the announcement, but two of the Carrionites are already there and use one of their dolls to render him unconscious.
The actors — thinking Shakespeare has passed out drunk — carry the playwright off stage and the performance proceeds.
The Doctor and Martha reach All Hallows Street and confront Lilith, who is expecting them. She confirms the Doctor's suspicions:
the three Carrionites hope to gain entry for the rest of their species, eliminate the humans, begin a new empire on Earth
and spread out from there. Martha, mimicking the Doctor's actions at Bedlam, tries to neutralise her by speaking the name
Carrionite, but Lilith mocks her, since naming only works once. Instead, she names Martha Jones, rendering her unconscious.
Lilith tries to do the same to the Doctor, but it fails to affect him, as she is unable to discover his real name. She
attempts to weaken him by naming "Rose", but he assures her that that name keeps him fighting. Lilith then feigns an attempt
at seduction, which brings her close enough to the Doctor to steal a lock of his hair. Taking flight through the window, she
attaches the hair to a doll — which the Doctor explains is essentially a DNA replication module — and stabs it
in the heart, whereupon the Doctor collapses. Assuming that he is dead, Lilith flies to the Globe. Martha wakes, and helps
the Doctor restart his left heart before the duo race to the Globe.
The actors have already spoken the last lines of the play, a series of directions and instructions that have opened a portal
allowing the Carrionites back into the universe. The Doctor tells Shakespeare that only he can find the words to close the
portal. Shakespeare improvises a short rhyming stanza but is stuck for a final word. Martha comes up with "Expelliarmus" and
the Carrionites — together with all the extant copies of Love's Labour's Won — are sucked back through
the closing portal. Martha, Shakespeare and the actors from the play are left to take the applause of the audience who believe
it all to be special effects. The Doctor meanwhile finds the three 'witches' trapped, screaming in their own crystal ball
and appropriates it for safe keeping in a "dark attic" of the TARDIS.
In the morning, Shakespeare flirts once more with Martha...and with the Doctor. He reveals his deduction that the Doctor
is not of the Earth and that Martha is from the future, once again proving his genius. For his "Dark Lady", he produces the
sonnet, "Shall I compare thee to a summer's day?" in her honour, but is interrupted when two of his actors burst in, heralding
the arrival of the Queen. Queen Elizabeth enters, recognises the Doctor as her "sworn enemy" and declares, "Off with his head!"
The Doctor is surprised at her outburst, since he says he has not yet met the Queen, but comments that he is looking forward
to finding out what he will do to offend her. He and Martha flee to the TARDIS, slamming the door just as an arrow embeds
itself in the TARDIS' exterior before dematerialisation.