When Earth is tearing itself apart by means of crime, pollution and war, aliens choose the time to invade, taking advantage of the lowering of everyone's guard. The Japanese government establishes an elite police organization known as Blue SWAT to combat the aliens, known as the Space Mafia. The aliens attack by possessing humans to obtain their goals. When an alien possesses the chief of the Blue SWAT unit to infiltrate the organization, it manages to completely demolish their building of operations and murder all but three SWAT members; Shou, Sara and Sig.

The Dairanger must save children who are transforming into playing cards by the powers of the Duke of Cards.

The Flashman find themselves protecting a puppy targeted by Mess due to it being the weakness of a chimera Beast Warrior.

Big Rally! Titan Boy! is the second movie of Choushinsei Flashman. It is a theatrical edit of episodes 15 to 18 (The Giant Robo is Worn Out, The Human Minimini Plan, The Mysterious Giant Reckless Car! and Big Turnaround! The Transforming Robo) with new and extended scenes.