MeltyLancer: The 3rd Planet is the third and final game in the MeltyLancer series of sci-fi police simulation games. This entry features a new main cast of characters, as well as significant differences in the simulation gameplay. Rather than training the abilities of individual officers through schedule management, this entry takes more of a business-simulation approach with the player sending lancer teams on group missions; the success rates of these missions affect public confidence in the government. Each Lancer's stats will affect their ability to successfully complete missions, and if too many missions are failed the game will be over. Battles may occur during missions, which take a semi-automated turn-based format.

In the year 2091, following a coup d'état on the planet of Karaba, a fleet of ships belonging to the Karaba Royalists approaches Earth seeking asylum. However, granting this request puts the Earth government at odds with the Karaba Revolutionary Army, who begin launching EMP terrorist attacks to pressure Earth into handing over the Royalists. As a new Public Safety aide stationed in Lunar City on the Moon, the player is tasked with responding to incidents and keeping the peace.