Colonel Dahar, leader of the Mars Imperial Army, has brought his forces to attack Earth, seeking to take the remains of an ancient civilization by force. A young girl named Momolita, living with an old inventor and a group of machine pilots in a small Earth city, seems to have some kind of connection to this mysterious ancient civilization. When Momolita is captured by the Mars Imperial Army, it's up to Ridegear pilot Ken and his friends to rescue her, and bring the fist of justice crashing down on Colonel Dahar!

Ridegear Guybrave is a side-scrolling action game with RPG elements. One or two players select from the four available characters, hop into their Ridegear mechs, and head out to fight for justice. Each character pilots their own unique Ridegear, and it is possible to buy a variety of different upgrades for each, including main and sub weapons, shields, and engines. Defeating enemies will also earn experience, and leveling up will increase each character's life meter and unlock new moves.

In addition to the main story mode, there is also a 1-on-1 Coliseum mode for one or two players. It is possible to use upgraded machines from the story mode, and new machines are unlocked for use as the story progresses.