Arato Endou and his faithful hIE, Lacia, have come together once again to show the world that artificial intelligence, no matter how brilliant, can be shut down safely. As they descend into the holding facility to confront Higgins, Lacia's AI creator, the pair must fend off enemies from all fronts. Among them are Snowdrop, a rampant hIE hellbent on devouring Higgins, and Methode, a hIE who seeks vengeance against Lacia. The world's super-intelligent AIs unanimously decide to terminate Lacia, whom they deem a threat to humanity. With limited time and the odds stacked against them, will Arato and Lacia be able to truly join together in a society where humans and hIEs can coexist peacefully? [Written by MAL Rewrite]

Recap episodes of Beatless.

With great advancements in technology, mankind has created hIEs, human-like robots that act as public and personal servants for society. Unlike many others, the kind-hearted high school student Arato Endou treats hIEs as equals, but his financial situation keeps him from ever owning one. However, his normal life is shattered when an ordinary run to the local grocery store goes horribly awry. Viciously assaulted by a hacked hIE, Arato is on the verge of death; but luckily, he is saved by an abnormal hIE carrying a weaponized coffin. Her name is Lacia, one of five highly advanced hIEs that recently escaped the clutches of the mysterious MemeFrame Corporation. Faced with a hacked car threatening to run them over, Lacia offers Arato a deal: in exchange for saving his life, he must register as her new owner, thus taking full responsibility for her actions. With little choice, he decides to trust this artificial girl and allows her to live in his home. Though Lacia begins to adapt to her new, peaceful lifestyle, she warns the entranced Arato of one thing—she does not have a soul. [Written by MAL Rewrite]

This is simply the OAV summing up the major events and battles of "Initial D 4th Stage" much like the "Initial D Battle Stage" original summed up the first 3 seasons. Additionally, has 2 extra battles from the manga that were not incorporated into the original 4th Stage. (Source: ANN)