Gray Mann's endless robot horde has overrun Earth. The mercenaries of Builder's League United (BLU) and Reliable Excavation Demolition (RED) are dwindling. The last Mann Co. factory has vanished, and Saxton Hale with it. Even Merasmus and the Bombinomicon are nowhere to be seen. Of the two teams, Medic, Soldier, Sniper, and Pyro are all that remain of BLU. Heavy, Demo, Spy, and Engineer comprise what is left of RED. In the past their companies had fought endlessly, but their only hope of survival was to work together. Unfortunately they were defeated in their last stand at Ghost Town, defending against the highly feared Wave 666. But instead of permanent death they find themselves brought to a different universe in a similar predicament, only the threat is otherworldly. Can the iconic and efficient mercenaries of Team Fortress 2 put their killing skills to use helping the shipgirls of Azur Lane defeat the alien Sirens once and for all?