Black Lightning's third season has been an eventful one and that's even if you take out "Crisis on Infinite Earths". All season long the Jefferson Pierce/Black Lightning and his family have been dealing with the ASA's occupation of Freeland, a difficult situation that has morphed over the course of the season to include a much more dangerous threat: the Markovians and, specifically, Gravedigger. Now, in the season finale, it's all come down to a final battle between Black Lightning and Gravedigger with the fate of Freeland all its residents hanging in the balance.
Spoilers for the Season 3 finale of Black Lightning, "The Book of War: Chapter Three: Liberation," below.
The episode opens roughly where last week's ended, with Jennifer/Lightning unconscious on the ground while Gravedigger and Jefferson/Black Lightning fight in the street. Gavedigger figures out Lightning is Black Lightning's daughter and Black Lightning in turn tells Gravedigger they, too, are related. The Markovians take Lightning. Elsewhere, Jamila Olsen is shot and presumably killed by Markovian forces.
While Grayle prepares to move people to the Pit for safety, Agent Odell pulls the plug on the ASA's Freeland operation and sends Major Grey looking for the briefcase. Gambi starts working with TC to try to find Lightning while, elsewhere, Lightning wakes up in a containment cell with Gravedigger trying to get her to trust him and sway to his cause. Jen is not having it. On the Freeland streets, Painkiller strolls up and takes out ASA agents, grabbing a weapon as he does. Lady Eve meets with Grey and lets her know that Gambi has the briefcase. When Lady Eve realizes they're going to nuke Freeland, a fire fight breaks out and Lady Eve is shot. She calls Lala and warns him.
Gambi finds where he thinks Jennifer is being held and Black Lightning and Brandon go to rescue her. Jace is tied up at Brandon's, but Commander Williams kills her as one of the "classified" elements he's supposed to destroy. On the streets, Henderson along with Two Bits and Lala and their forces form an unexpected alliance to take down Markovians. Williams shows up to kill Lynn next, but she gave herself metaboost and survives. She continues working on an anti-booster to stop Gravedigger.
Painkiller is preparing to kill the Pierces when, in the mindscape, Khalil makes a play to take back control and wins.
Henderson, in the woods, comes upon Gravedigger and his forces as they prepare to go to the Pit. The resistance tries to fight him, but he uses his powers to make them all "sleep" so that he can proceed. Thunder and Grace usher the metas into a safe room but Gravedigger shows up and mind controls Grace into attacking Thunder. Outside, Henderson comes upon Markovian's about to attack Black Lightning and stops them, but is mortally wounded in the process. Black Lightning sits with his friend as he dies.
At the Pit, Thunder takes a beating from Grace, but ultimately knocks her out. Gambi tells Thunder to stay on mission and they'll come back for Grace. Lynn comes up with a plan to take down Gravedigger and Black Lightning agrees to it. Lightning and Brandon confront Gravedigger and hit them with their combined powers, briefly holding him off. Odell initiates the self-destruct, giving the Pit ten minutes before it, too is gone.
Lynn shows up while Gravedigger and Black Lightning fight and shoots him with the boost antidote. Lynn and Black Lightning escape right before the Pit blows up, leaving Gravedigger behind. Odell gets into a car to leave Freeland and is confronted by Khalil who shoots him through the spleen and leaves the injured Odell for Black Lightning to handle.
ASA forces attack Gambi's in search of the briefcase and fight their way into the bunker, but are taken out by Gambi and TC. At Anissa's Lynn breaks the news to her daughter that Grace is in a coma and needs to be in a facility where she can get constant care. In Markovia, Tobias has killed the Markovian who tormented him and, after watching a news report decides to head back to Freeland. In Gotham City, Lynn continues taking Glimmer and testifies at a commission and gets funding for a metahuman boarding school. Black Lightning hands over the briefcase. The ASA is disbanded, Odell will be prosecuted. It's revealed that Gravedigger has survived as well, walking away after a bit of shapeshifting of his own while the Pierces leave the hearing, united.