It's time for Flurry Heart to start using the potty. Judging by her past behaviour though, this might be quite a dangerous proposition... Fortunately, like always, Auntie Twilight has a plan to make things work out... But will it work?
Flurry Heart is a grown mare (16 years old) now, MOM! Her parents just don't get it. At least Uncle Anon is here to listen to her... for better or for worse.
After being invited for a visit to the Crystal Empire by Cadence, Chrysalis is suddenly left to spend the day with Shining Armor and Flurry Heart at the traveling fair.
With everypony else unavailable, Spike volunteers to babysit Flurry Heart for the day. Things go well, but then Sweetie Belle comes and shakes things up by deciding to help, too. The day goes on, and they spend it like their own, little family.
While Spike has a night out with his siblings, Flurry Heart and her friends have a sleepover in the now-renovated Harmony Clubhouse tree, but their bickering welcomes in a very powerful ghost that seeks to turn them all against one another.
As a budding diplomat, Flurry Heart often travels out of Equestria and into other dimensions. It's not uncommon for her to get stalled in the Between Place, but something is different this time. Someone else is here.