Following the events of "Three's a Crowd," Cadence tells Shining Armor about her time with Twilight and Discord over a crystal mud bath with her husband.
Following the Changeling Invasion of Canterlot, Twilight's friends, Princess Celestia and Shining Armor lament over how they failed to protect Canterlot from the Changelings as well for their behavior towards Twilight at the Wedding Rehearsal.
Many ponies played their part in creating the Equestria we know and love, one of them is Starry Night, guildmaster of the Knights of Night, and this is part of his story.
Luna and Octavia are busier than ever with the Grand Galloping Gala fast approaching. Both of them have a long night ahead of them, and if all goes well should meet the next morning for breakfast.