Horizon Protocol cover art

Horizon Protocol

Null Sequence (Variant Wars, Book 1)

Preview
Try Premium Plus free
1 credit a month to buy any audiobook in our entire collection.
Access to thousands of additional audiobooks and Originals from the Plus Catalogue.
Member-only deals & discounts.
Auto-renews at $16.45/mo after 30 days. Cancel anytime.

Horizon Protocol

By: Callum Brown
Narrated by: Sean Letourneau
Try Premium Plus free

Auto-renews at $16.45/mo after 30 days. Cancel anytime.

Buy Now for $9.68

Buy Now for $9.68

About this listen

They promised a cure. What they meant was control.

Lena Vale thought she was doing the right thing—signing up for the Horizon Protocol to rid herself of the abilities that made her dangerous. Instead, she wakes in a facility built to dissect the Variant gene. Her power isn’t being removed—it’s being mapped, copied, and stored.

Ethan Vale, her estranged brother, has spent years suppressing his own gift. But when Lena disappears, he’s forced to confront the truth about Horizon—and the past he’s tried to forget.

As their powers resurface, and their connection deepens, they uncover a terrifying plan: Horizon isn’t curing Variants… it’s harvesting them.

Horizon Protocol is the explosive first entry in The Variant Wars trilogy—where identity is weaponized, memories are currency, and evolution has a cost.

©2025 Callum Brown (P)2025 Callum Brown
Genetic Engineering Science Fiction Technothrillers Thriller & Suspense War
No reviews yet
In the spirit of reconciliation, Audible acknowledges the Traditional Custodians of country throughout Australia and their connections to land, sea and community. We pay our respect to their elders past and present and extend that respect to all Aboriginal and Torres Strait Islander peoples today.