From the publisher:
Dark Horizons - Lore is a game of mechanized combat set in a world shattered by war. Set in the early 2160s, this game simulates combat between the remotely controlled mechanized assault vehicles of two opposing factions in the Dark Horizons Universe: the Federated States and the Eastern Confederation. The Dark Horizons Universe has a deep and lengthy history of which Dark Horizons - Lore is only a small part.
Dark Horizons - Lore d20 Edition (d20 Lore, for short) uses the rules in the d20 Modern Roleplaying Game Core Rulebook and d20 Future as the foundation for play. All rules in this supplement are exceptions or additions to the rules in those guides. Mechanized Assault Vehicles (MAVs) are treated as a blend of Vehicles (d20 Modern Roleplaying Game Core Rulebook Chapter 4: Vehicles) and d20 Future Mecha (d20 Future Chapter 9: Mecha).