It is Twilight's first Hearth's Warming Eve as ruler of Equestria, and although Twilight is happy with her new duty, she feels alone without her friends to keep her company.

Of course she knows that her friends are probably celebrating with their families, but Twilight wanted nothing more than to celebrate that date with somepony very close to her. Until somepony comes to spend that holiday night with her.

This story is a sequel to Written in the Stars

Rarity has been dating Luna for some time, although it hasn’t yet become common knowledge.

As the couple look forward to their first formal engagement together, Rarity is getting nervous, but this is not destined to be the biggest problem she has to face …

Love can strike when you least expect.
Sometimes it’s just when you see an old friend in a new light.
This is what happened to Princess Luna and Rarity, both of whom admired each other, but never in a romantic way.
All that was destined to change.
It was written in the stars.
Luna x Rarity

This can be read as a stand-alone story or continued to its sequel Luna's First True Love, when we find out about the mysterious pink unicorn in Luna's precious oil painting.

There is another sequel, A Hearth's Warming to Remember, that follows Luna and Rarity to their first Hearth's Warming together.

After the events with the Tantabus, Luna thinks she's got everything under control. However, when Twilight drops in to pay her a visit, she starts to question her own actions.