Once a peaceful Earth city, it's now a haven for criminals aided by the nefarious Alienizer arms dealer, Agent Abrella.

Now it's up to Ban Akaza and the Special Police Dekarangers to protect the Earth from the invading Alienizers and finally bring peace and justice back to the planet.

from Agent Abrella's scheme, the Dekarangers parted ways with Ban joining the Fire Squad, Jasmine marrying Hikaru Hiwatari (who had graduated in the Space Police Academy and grown close to Jasmine when he met her again after being assigned to the Earth Branch), and Swan working independently while Tetsu, Hoji, Sen, and Umeko continue working under Doggie Kruger.

But after an incident occurred that hospitalized Kruger on planet Revaful wherein he was labeled as a dirty cop for an apparent dealing with the Qurlian Crime Family, which went awry with the death of a civilian witness, Tetsu takes over the Earth Branch.

When Ban is ordered to return to his branch on orders from the Galactic District Police Bureau chief Kight Reidlich, Tetsu decides to have his team oversee the escort, but the escort ship is sent crashing onto the barren planet Riiyo where the Dekarangers fend off the Mechanoids before Deka Blue runs off with Deka Green following him to the Mechanoids' ship while Umeko learns that Assam and Mugi are part of the party keeping Carrie from reaching Gowashichoru as they take her to their boss.