King Sombra goes to Canterlot.

Princess Luna fills her thoughts with him.

Celestia hates Sombra due to being embarrassed in front of him and because he
paid more attention to Luna.

But if Luna fell in love with Sombra... What would happen if Celestia found out?

Based very loosely on the “Remembrance” series by Ashley H on YouTube. https://youtube.com/playlist?list=PLC07Pw1hRqfULci9RsYd2pAwR6C3WG7rt

During the three years since the assassination of her father, eighteen-year-old Princess Flurry Heart has been locked away in the Crystal Empire’s castle by her overprotective mother, Princess Cadance, who is in perpetual mourning. Flurry longs to explore the world beyond the castle walls, so she tries to stage an intervention for Cadance with the help of her three powerful aunts, Celestia, Luna, and Twilight Sparkle—along with a very special royal guard.

After Spike learns how Rarity feels, he is angry, upset and feels used. Spike feels like he can't fully open up to anyone about what happened. After having a dream where he spoke to Princess Luna, he ends up going to Canterlot to see her, as he remembered that Luna has helped him in the past. He needed to talk to someone and get it off his chest. After speaking with Luna and spending a few days in Canterlot with Luna, Spike starts to see the Princess of the night in a different light. Does this mean that he is over Rarity? Is this connection a strong friendship or something more?

Sources for cover images
https://www.deviantart.com/rossdubyah
https://www.deviantart.com/coltsteelstallion
http://www.handandbeak.com/2019/07/spike-rarity-vector/png-spike-rarity-deviantart-pony-spike-vector/

Princess Luna is all too familiar with feeling inadequate, but she never really thought her experiences with feeling overshadowed by Celestia would ever help anyone else. Her thoughts prove to be untrue when she realizes that she is a major role model and positive influence for Princess Cadance and Shining Armor’s youngest daughter, her beloved great-niece, Princess Skyla. The filly adores and idolizes Luna, who is more than happy to take Skyla under her wing.

While Flurry Heart is the heir to the Crystal Empire and has all the support she needs, Skyla is often unintentionally neglected by her parents, so she considers Luna to be more of a second mother to her than an aunt. Whenever Skyla feels alone, needs advice, or just needs somepony to talk to, she runs to Luna, who will be her defining influence as she grows up.

An unknown stallion of no notoriety comes into contact with a wagon that had seen better days, and the mare who owned the broken wagon. He's seen, and heard, of this mare before and her accolades as a sort of performer. But he noticed she wasn't doing so well. The stallion decides to present himself to her and attempt to get the mare back on her hooves.

Equestria is ruled by three Alicorns: Celestia, Luna, and their brother Drake. The story follows Drake as he is banned and mostly focuses on his return to Canterlot to reveal the truth behind his banishment