Heroes vs. Trial and Error

 marks the battle between the villains Trial and Error, and a group of cooperating hero teams led by Breakthrough.

Prelude
After the remaining members of the Fallen sabotaged the City's portals, crime in the City increased, and the heroes became less effective at responding to crime, due to the stranding of several key Wardens. As a result, Breakthrough began an effort to organize a hero network, sharing information and communicating between them. They began to contact various hero teams with proposals to cooperate, including Advance Guard.

The Hollow Point villains were another group hit hard by the raid on the Fallen compound. The leader of the Hollow Point group, Prancer, organized a mission to steal several trucks of livestock, with the capes Trial and Error accompanying them. Three members of Advance Guard, Spright, Shortcut, and Flapper, pursued the trucks. Mayday eventually called in Breakthrough to assist.

Battle
Capricorn, Antares, and Tress of Breakthrough intercepted the chase, joining with Advance Guard's patrol group. They succeeded in knocking over one truck, and stopping the others, leaving the heroes to fight the villains in person. Using his chains, Trial hit Tress, piercing her body, and Antares was caught by Error's Stranger power, preventing her from deflecting the attacks. As Antares focused on repairing Tress's body, Trial attempted to get the heroes to stand down, threatening Antares and Tress, as well as the civilians in the cars, before attacking.

Despite being outnumbered, Trial's offensive and defensive power and Error's interference proved to be problematic, and Advance Guard decided that a continued fight wasn't worth it, letting the trucks leave. However, Breakthrough subsequently called for reinforcements, and discovered that Trial and Error were working for Prancer.

Spright and Shortcut continued to pursue the villains. Heroes including Fume Hood, Tempera, Lighter, and Foxtrot came in as backup, and were briefed on Trial and Error before joining the pursuit. They eventually reached the drop-off point, where Trial and Error were joined by three other capes and a crowd of armed henchmen. The hero's Movers worked to harass the villains, while the remaining members of Breakthrough showed up, Swansong and Precipice by projection, and Cryptid in his Brooding Anger form.

The civilians were evacuated. The less mobile heroes reached the site, and began their attack. The three Hollow Point capes, Cleat, Etna, and Crested, were defeated without much issue; cornered, Trial and Error surrendered, and Advance Guard began the arrest.

Aftermath
Trial and Error were presumably arrested, as were the three Hollow Point capes. As the heroes' cooperative effort proved successful, Breakthrough's network began to gain traction, with teams such as the Steelmasons, Auzure, and Shorewatch coming on board.