Two warring planets are having their rulers marry to ensure peace before they go and destroy each other. As is so often the way, the bride is being ferried like a token/prize to a planet she has never visited and whose inhabitants she abhors. Her people have tempers and guess whose job it ends up being to teach her about how she will have to conduct herself among her new people.
That’s right, good-old crack-flavored-lip-balm Kirk. To be fair though, he only became her teacher after the supposedly-peace-loving-but-equally-stubborn teacher sent by the groom got stabbed for entering the bride’s quarters without permission.
So Kirk goes to teach her, but her old teacher warns that what makes the women of her world so alluring are their tears which hold an incurable biological agent that once absorbed into the skin of any male binds him to her in a way comparable to a puppy imprinting on its owner.
As you may have guessed, an apparent moment of vulnerability makes her cry and Kirk can’t help but wipe the tear from her eye and that’s it. They do that thing where they close up on a woman’s face to signal that Kirk finds her attractive, but the face she makes is confusing because she looks like she just won a prize at the fair. She looks like she wanted to trick him, which would have made for a much more compelling episode with Kirk being so irrevocably taken in by a woman.
SPOILER: the episode instead progresses so that we see she actually cares about Kirk, enough to do as he wishes and make the most of the arranged marriage the counselors of her planet forced her into. Thus the poem:
Sonnet 35
The tears that piqued your kindness once
will never fall again; I stand —
now reliquary as a dunce
who only wears the cap at hand —
as tall as any mourner’s glass
with filigree of fine-wrought brass,
the stopper fixed for no escape
as to my duty I take shape.
To each his own as fate decrees,
so we regard as we part ways
and never more speak of this blaze.
To each his own by choice degrees,
as one will honor your word
and every second see a third.