Following a global war and climate change, 35% of Earth's land mass has sunk into the ocean. In this difficult time, countries rely not on armies but on private military corporations to provide security against constant terrorist attacks. One such company is Arqon Global Security, whose staff of mercenaries is tasked with protecting Daiva City on a pay-per-mission basis. Armed with motorcycles that transforms into weapon-wielding mecha, these "blademen" are none too popular with the people they protect - but they always get the job done!