Slaughterhouse Nine Hold Apartment Hostage marks the battle between members of the Slaughterhouse Nine and heroic allied forces.
The heroes have just finished the Battle at Schenectady when they receive word that two more battles have started. Golem leads the Chicago Wards to fight to one location, while Weaver leads the Undersiders and the Brockton Bay Wards to the other.
Using Vista's power, they break through into the sealed building. They first meet a Mannequin, and after a brief skirmish, the Mannequin closes their entrance tunnel. They start to climb the stairs, but are interrupted by a Murder Rat, who is frozen by Clockblocker after she slashes Vista's face. A different Murder Rat is killed, and two Mannequins enter the battle, fighting Grue. The first Murder Rat unfreezes and teleports to Vista, but is killed by Weaver. The third and last Mannequin loads himself up with Breed's bugs, and jumps down. The bugs attack the group, distracting them.
The last Murder Rat climbs up from below, and is tagged by Clockblocker. Unfortunately, this stops Grue from using her power, and he is forced to use the Hatchet Face hybrid's power to take out the remaining two Mannequins, one having been killed by Bastard. This stops the other heroes from using their powers, allowing the bugs to gain more purchase on their bodies. He moves away quickly, allowing them to kill the rest of the bugs.
They arrive upstairs, where Tyrant waits. He is quickly killed by Foil. Several Breeds wait among the hostages, and are killed by Crucible. A Nyx is hiding in Mannequin made coffin, pretending to be a teenage boy disguised as Jack Slash (Reword). The Nyx tells the heroes that Jack is heading towards Ellisburg in return for being released, but they burn her anyway.
Weaver heads towards Ellisburg while the others travel towards other situations that have turned up.