Roberta, the terrorist-turned-maid that made her appearence in the first season of Black Lagoon, returns in this five-episode OVA series—and this time, all bets are off! Roberta's benefactor, the patriarch of the Lovelace clan, is murdered during a political rally. The assassin's trail soon leads back to Roanapur—so now she has returned on a mission of vengeance! However, close behind her is the new patriarch, Garcia, as well as Roberta's apprentice (and maid), Fabiola Iglesias. As the body count of Roberta's bloody rampage mounts, forces from within the corrupt island (which includes the Lagoon Company), as well as overseas converge on what threatens to escalate into all-out war!

Rokurou "Rock" Okajima has joined the Lagoon Company, a pirate mercenary group which operates out of Roanapur, Thailand. Despite his initial protests, this filthy slum of depraved souls and merciless criminals now serves as the former salaryman's home. Stranded, with nothing left of his past life but the clothes on his back and his inner morality, Rock is forced to perform jobs alongside the other members of the Lagoon crew. Berated for his lack of spine as he wades through the underbelly of society, he must decide whether to continue on amidst the gunfire and ruthlessness or risk everything he has in an attempt to be free. Whether he chooses the comfort of a familiar land or the freedom of being an outlaw, his decision will have lasting consequences on the crew who gave him a home.

Within Thailand is Roanapur, a depraved, crime-ridden city where not even the authorities or churches are untouched by the claws of corruption. A haven for convicts and degenerates alike, the city is notorious for being the center of illegal activities and operations, often fueled by local crime syndicates. Enter Rokurou Okajima, an average Japanese businessman who has been living a dull and monotonous life, when he finally gets his chance for a change of pace with a delivery trip to Southeast Asia. His business trip swiftly goes downhill as Rokurou is captured by a mercenary group operating in Roanapur, called Black Lagoon. The group plans to use him as a bargaining chip in negotiations which ultimately failed. Now abandoned and betrayed by his former employer, Rokurou decides to join Black Lagoon. In order to survive, he must quickly adapt to his new environment and prepare himself for the bloodshed and tribulation to come. A non-stop, high-octane thriller, Black Lagoon delves into the depths of human morality and virtue. Witness Rokurou struggling to keep his values and philosophies intact as he slowly transforms from businessman to ruthless mercenary.

A.D. 2016, the foundations of humanity have been incinerated by the Mage King Solomon. Chaldea, a secret mages organization with the mission to preserve humanity's future, foresaw mankind's extinction in 2015. Thus commenced the operation to repair the Singularities in history caused by Holy Grails dispersed across time and space—Operation Grand Order. Using the Rayshift time travel technology, Chaldea's last master Ritsuka Fujimaru and his demi-servant Mash Kyrielight have traveled to and resolved six Singularities. Now, they depart for their most dangerous destination yet: a civilization in the Age of Gods, B.C. 2655 Mesopotamia. Ritsuka and Mash soon discover that Demonic Beasts roam the land, attacking people and towns. Amidst chaos and terror lies humanity's last defense—Uruk, a fortress city that acts as the frontline for the battle against the beasts. The battlefront is commanded by none other than King Gilgamesh, the King of Heroes, who sought aid from Heroic Spirits and took on the role of a mage to protect his city. Along with Gilgamesh and the summoned servants, Ritsuka and Mash must protect Uruk against the magical beasts' onslaught and defeat the Three Goddess Alliance who aims to eradicate humankind; all the while, a greater threat looms over Uruk, preparing for its awakening. [Written by MAL Rewrite]