Princess Celestia and Princess Luna seemed to be having a friendship problem. Twilight Sparkle is hesitant to send Starlight Glimmer, despite what the Map says. When Starlight arrives in Canterlot, she can see the sisters resent each other ... But what's the best way to tackle it? Besides, well, switching Cutie Marks?

[Another approach to A Royal Problem, combined with things from Between Dark and Dawn]