This story is a sequel to Bookends Part 3: Or Family Values

Life in Ponyville goes on as normal for the next eight years. The dangers and trials for the Mane 6 appear to be something of the past. The ponies of Ponyville have all but forgot the hazards of the past.
The group of friends continue growing as close as ever. With the inclusion of Pinkie’s wife Trixie, and the now accepted fact that Pinkie is a Changeling, there seems to be nothing the group couldn’t handle.
But with the responsibility of three growing and precocious foals; Celestia and Luna Sparkle and Zap Apple, Twilight, Cheerilee and Rainbow have their hooves full.

But when a warning of another threat against Equestria from Princess Celestia comes to Twilight, the mothers fear what could happen when they have children to consider.
If the safety of Equestria is to be maintained, a different view of harmony may have to be accepted.

As is normal with life, things happen that we don’t expect. And a hidden past almost never stays hidden…