In an attempt to put to rest a nagging question Twilight keeps bringing up, Rainbow Dash agrees to do some genealogical research into her family tree. Imagine her surprise when she finds out that Daring Do is a part of it.
In fact, Daring Do isn't some distant relative or lost cousin, she's the younger sister of Windy Whistles. A revelation that has never before been disclosed for reasons unknown.
Armed with this knowledge, Rainbow sets out to get some answers from none other than the newly discovered link herself, Daring Do. There must be a good reason why she's neglected to inform Rainbow of their shared connection all this time, right?
(An indirect tribute to Sir Sean Connery.)