The War for Freeland was an attempted invasion on Freeland by the Markovian military. Wishing to create a place for stable meta-humans to live, Markovia sent much of their military to take the city for themselves. However, they were opposed and eventually pushed back by Black Lightning's team, the A.S.A., the Freeland Police Department, The Freeland Resistance and Latavious Johnson's gang.
Markovia at some point became interested in Freeland and their meta-humans, forcing the A.S.A. to turn them into potential weapons to fight back against a potential invasion. Soon after, Markovia sent Colonel Yuri Mosin and various soldiers to infiltrate the city in preparation for an invasion. The A.S.A.'s attempts at defending the city then became frowned upon, leading to Black Lightning and many others to oppose the agency from their brutal tactics. This internal struggle allowed Mosin and his soldiers to abduct both Lynn Stewart and Helga Jace in pursuit for a stable meta-human serum in order to create more meta-humans. However, the A.S.A. and Black Lightning joined forces to create a team to take them both back. Following the success of their mission, Yuri Mosin was subsequently killed, with dangerous meta-human Tyson Sykes assuming command of the soldiers. The Markovians then returned to Freeland and began an all-out war on their civilians, leading to Black Lightning's team, the A.S.A. and the Freeland Police Department to desperately defend the city.
Once the Markovian soldiers decided on an all-out assault on Freeland, the A.S.A. began evacuating and started tying up loose ends. Agent Odell had Major Sara Grey locate the briefcase containing evidence of their wrongdoings. Jamillah Olsen attempts to report the situation but is gunned down by one of the Markovians. Their leader, Tyson Sykes, finds himself facing Black Lightning after defeating his daughter, Lightning. This then leads to Lightning getting abducted by his allies and forcing Black Lightning into a hasty retreat after being outmatched. A.S.A. Commander Carson Williams then murders Helga Jace, one of the few who knew of the agency's misdeeds, and tried to kill Lynn Stewart only to fail upon doing so. Lynn, using a temporary meta-human power, accidentally kills Williams after trying to reason with him. Grey contacts Lady Eve in order to garner a location on the briefcase. However, Lady Eve discovers that the A.S.A. are planning to bomb Freeland to prevent the Markovians from taking it and begins a shootout, leaving her critically wounded. Back at the Freeland Police Department, Bill Henderson is seen evacuating people to a safe location when more Markovians move in. Luckily, the tide turns when Lala and his allies defend Henderson and the police. Gardner Grayle and Erica Moran are seen in Garfield High School, which has seemingly been converted into a rescue shelter for the survivors.
Later, Gardner Grayle and Erica Moran were contacted by Peter Gambi to go to The Pit and bring the meta-humans inside as the Pit has a room that can prevent a nuclear blast. Black Lightning's team rushed to The Pit in order to prevent Tyson Sykes from getting their powers. After they arrived, Gardner and Erica were unconscious as Tyson Sykes has arrived and made them sleep. However, several Markovians soldiers were about to kill Black Lightning and was stopped by Bill Henderson, who later shot to death due to the lack of firepower. After the team mourned for him, they split up into three teams, Thunder and Grace to protect the meta-humans, Lightning and Brandon to slow down Tyson Sykes and Black Lightning to find Lynn. During the fight Tyson was able to make Grace fight Thunder and he escaped. Luckily, Lightning and Brandon figured out that volcanic-lightning can penetrate Tyson Sykes's magnetic field. However, it is not enough and Black Lightning arrived for back-up. Meanwhile, Odell set a timer for the Pit to explode and left. Sara Grey later brought a squad to Gambi's Custom Tailoring for the briefcase and were all killed by Peter Gambi and TC. After Tyson was shot with Anti-booster serum, he was unable to use his powers and was knocked out by Black Lightning. The Pit later exploded and Tyson was able to escape. 
A few days after the war, the team was brought to Gotham City for a trial. Eventually, the A.S.A. was disbanded and Odell was incarcerated. However, Grace was unconscious after suffering from a hit of Thunder and Tyson Sykes escaped with an image inducer. 
A year later, Tobias Whale returned to Freeland and began to invest in resources to help reconstruct the war-torn city, which had many homeless people, including the family of Marcel Payton who lived in his car.
Behind the Scenes
- Due to Black Lightning being filmed far away from the rest of the Arrowverse shows, a crossover with other heroes assisting in the battle was not possible. In-universe, this is due to the A.S.A. blocking the truth and communication with the outside world.