The Last Sentinel is the story of Frost Windchill, a unicorn cryomancer and the supposed descendent of a Lunar Guard. This is the tale of his life, starting with a fateful encounter with a Stable engineer and repairpony named Rig. Together, they- and others- seek to render aid to her Stable. Along the way, Frost and Co. unravel a mystery behind a high-tech, radical organization of griffin mercenaries known as "The Dead Boys," whose leaders are the spitting image of the griffin pantheon of gods, goddesses, and icons.
And they also unravel the mystery behind Frost himself, for there is more to him than meets the eye...
Frost Windchill is known to be a storyteller of sorts. Comfortable with telling the occasional sprite tale or legend, a child approaches him one day and asks for a real story.
And so Frost tells one- the story of his life. It's not a typical story, and there's more to it- just as there's more to the descendant of a Lunar Guard. It's a story not just of himself but the heroes he stood beside- big and small, legendary and obscure. But there's something amiss, buried lies between the lines.
After all, it's hard to kill memories when you remember everything.