The original Blue Seed ended with closure that mattered. This OVA throws that away and moves the fight to San Francisco with logic that doesn't hold. Episode three is genuinely good, though, the hot springs sequence has actual breathing room, the fanservice lands because the show isn't desperate about it, and there's enough character work to remind you why you cared about these people in the first place. If you can forgive a premise that makes no sense, there's real fun waiting in the back half.
A disgraced researcher operating out of San Francisco has cracked the code to manufacturing monsters from scratch. Unlike the ancient Aragami that once plagued the world, these artificial creatures emerge without divine intervention, making them unpredictable and impossible to control through conventional means. When California descends into chaos under their assault, the American government realizes it needs experts who've already faced the supernatural before. They call back the scattered members of TAC, the international organization that spent years battling otherworldly threats. The team reluctantly reunites, finding themselves in unfamiliar territory both literally and figuratively. West Coast operations, rogue science, and creatures engineered with unknown purposes force them to confront whether their old playbook even applies anymore. Between the monsters multiplying in frequency and the scientist's true agenda remaining hidden, they question whether they can stop what humans created without understanding why.