I've just released the next Supreme Outer Guardian Series (SOG) - Brink's End. It's longer than my usual series, as it follows multiple characters at once. It really advances the SOG story line and fleshes out the shadowy enemy, the Underside. If you liked Mercury Nova, the 3rd SOG Series, you'll love Brink's End.
As usual, the first book is free from most online retailers I stock at, or you can get it right here from this website.