Underground: An Alien Invasion Military Sci-Fi

by Caleb Fast

There's a secret beneath the Bulwark...

It seems that the more time Matthew spends on the front the more things he finds.

Sometimes those discoveries are enclaves of ancient AI killer robots, sometimes it's a bunker, and other times, it's something even more unexpected than all of that.

In this case, that underground discovery is something that will change the way everyone in the Bulwark can live for the better.

However, mystery surrounds it and its discovery opens up more questions than Matthew is ready for. Read on to find out what it is!

Read The Battle for Underground Today!!

Underground is the nineteenth book in the military science fiction series The Battle for Allegra. Dive into this tale as Matthew fights off aliens and an oppressive Galactic Empire. If you love reading tales of sci-fi action, rebels, and aliens, then Underground is the book for you!

This is the military sci-fi you've been waiting for. If you loved Star Wars, Stargate, and The Expanse, then you're sure to love The Battle for Underground.

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The Battle of Allegra is a short story series that is intended to be read in order! Each episode (which will be at least 10,000 words long) tells more of the story. Join in and read them today to see what befalls both Matthew and an entire planet which are both thrust into war they didn’t ask for.

69 pages, Kindle Edition

Published February 1, 2022

About the author

Caleb Fast is the author of a growing collection of Science Fiction titles. His series The Battle for Allegra is his most popular by far, and is the focus of most of his efforts of late. His flagship series, The Limit of Infinity is still growing as well, as is its following. He enjoys writing on a range of science fiction subjects, and can't go too long without writing some sort of battle. However, Caleb does a lot more than writing. He also enjoys going on long hikes, long drives, and is a devout bookworm. In addition to all of that, Caleb runs his own antique bookstore and a few other gigs too.

Caleb currently resides in the Pacific Northwest, just outside of Portland, Oregon.

Check out my website!
calebfast.com
Or, check out My Facebook Page!
facebook.com/TheLimitOfInfinity/

The Limit of Infinity
-Renaissance: The Limit of Infinity
-Escapade: A Price to Be Paid
-Overcomer: No Man Left Behind
-Wayward: Long Way from Home

The Battle for Allegra
-The Battle for Allegra: Conscripted
-The Battle for Allegra: First Kill
-The Battle for Allegra: The Hunt
-The Battle for Allegra: Relegated
-The Battle for Allegra: Retrieval
-The Battle for Allegra: Sanctuary
-The Battle for Allegra: Secured
-The Battle for Allegra: Harborage
-The Battle for Allegra: Revelations
-The Battle for Allegra: Promotion
And a whole lot more!