No more than five years after the Royal Wedding, the megaspells fell all over the globe, thus ending civilization as it was known. However, ponies and other species which dwelled in equestria survived in the stables scattered around the land. Other species managed to survive, either through radiation spells, private bunkers, or by surviving massive doses of radiation. That and by hiding, deep beneath the changeling hive, where the entire changeling race fell into hibernation. Now, a century later, the hive is found, and what awakens in its depths, is hungry, deadly, and on a time limit. Queen Chrysalis must set out in her weakened state to find a source of love, or her children will die, and shortly after, she will follow suit.

100 years after the Gardens of Equestria activated, the New Equestrian High Council has maintained peace throughout the nation. Now that there is peace, one ambitious creature wants to rebuild. Only, he wants to rebuild and entire species.

He can not do this alone. With permission from the High Council itself, he has taken with him, two ponies from the military. They will travel through lands still wild, and even lands not explored for a millenia.

When a new planet suddenly appears out of nowhere, it draws the attention of the UNSC and Covenant. It's up to a lone Spartan to save the day, at first. When the natives of the planet decide to join him in the fight against the Covenant, the war gets that much more complicated.
Not best description. It's Halo so foul language possible.