(Prequel to "Birthday Built For Two".) On a trip to the Crystal Empire, Starlight finds Sunburst acting rather strange. Before she has a chance to ask him though, she gets roped into helping him foalsit Flurry Heart for a day.
While waiting for the train to arrive to take them back to the Crystal Empire. A series of unfortunate events occur with Flurry Heart losing her favortie toy whammy.
Sunset Shimmer and Equestria’s own Princess of Friendship Twilight Sparkle have spent hours, literally hours, researching earth baby intelligence and have come to some startling conclusions regarding human Flurry Heart.
When Sunset reveals that the reason she does not want to have talks with Twilight about the possibility of having children is that she has doubts about being a mother, Twilight decides to volunteer the two of them for babysitting
Flurry Heart's birth fulfills a dark prophesy of doom, setting forth calamitous events as reality tears apart, underworld invaders attack, and vile cultist emerge. The Crystal Empire faces a dire threat from an adorable dark new master.
Princess Flurry Heart has found something at school that she wants more than anything else in the world. Something she will do anything to get. Something that an unsuspecting young colt has. An extra cookie.
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?
Princesses Celestia and Luna are watching 2 year old Flurry Heart, who wants to play. Luna teaches her a game from a thousand years ago. What could go wrong?
They thought it was over. They thought they were safe. They thought everything would return to normal. But everypony forgot one very important, itsy-bitsy, adorably destructive, tiny little detail.
Sunburst is Flurry's foal sitter while Cadence and Shining go out on vacation. While as a foal he and Flurry Heart become seperated and the two go on journey to be reunited.