Inspired by Learning to Forgive by The Fields of Ice. Twilight has diplomatic duties as princess, which require her to travel for extensive periods of time. Spike is dragged along. Eventually they fight, and Spike leaves. He originally intends to return to Ponyville, but after some thinking about how much he's missed out on because of Twilight, he instead goes to Canterlot and knocks on Moondancer’s door, asking to spend the night. Moondancer, surprised at seeing him, agrees. Main story starts the following morning, and will tell from Spike's, Moondancer's, and Twilight's perspective separately.
For Spike, the story is about figuring out his own place in life. The main idea here is that, in a sense, Spike has put his life on hold so Twilight can live hers. He left his friends in Canterlot so Twilight could stay in Ponyville. He stayed to clean while the Mane 6 had fun etc. As he reconnects with Moondancer and other members of the Canterlot 6, he needs to decide if he wishes to stay as Twilight's assistant, or if it's time for him to start living for himself. Concurrent to this will be the decision as to if he wants to stay friends with her, and if so, what sort of friendship he wants. This decision would be the end of the story, minus any epilogue.
Moondancer’s storyline is about her own feelings on friendship, and deciding whether or not to open herself up after getting hurt the last time. Key part of this will be reconnecting with the others of the Canterlot 6. In the story, though she will be reluctant to make friends at first, she will never openly say this to Spike (sets up a possible Spikedancer scenario, if desired). Her major moral decision will be whether or not to forgive Twilight for hurting her the way she did. As such, a confrontation with Twilight is a must, and may serve as the final plot device for the story before Spike's decision is made.
Twilight’s storyline involves figuring out Spike’s place in her life, as well as her trying to balance her duties as a princess with her duties to her friends. She will go to Ponyville to search for Spike at first, but heads to Canterlot after Celestia informs her of Spike’s location. Rarity will accompany her, Fluttershy and Applejack will not (animal/farm duties). Pinkie and Rainbow may or may not depending on if they can be made to fit coherently. In Ponyville, Twilight should discover a massive change with her friends (Rainbow becoming a Wonderbolt, Fluttershy and Discord being engaged etc.) that kick-starts her self reflection.
The ending is variable, depending on which decisions each of the characters make (Spike still wants to be friends, Moondancer accepts or rejects friendship, Twilight can or can't balance friendship with princess duties).