On their first trip together, the Doctor transports Martha Jones to 1599 London where they go to the Globe theater and meet William Shakepeare who announces on stage that they will perform his new play, Love's Labour's Won. As history doesn't record such a play having ever been found, the Doctor knows that something is amiss. The Doctor soon discovers that three witches, the last of the Carronites, are casting spells and using the power of words to revive their kind. Fortunately, the Doctor and Martha have someone on their side who also has a unique ability with the English language.
—garykmcd