In the third episode of the series, Invincible embarks on his college journey. Embarrassed by his collection of toys, Mark hastily discards them all into a dumpster, sparing only his cherished Seance Dog. His new roommate, William, quickly familiarizes Mark with the quintessential college ritual of hanging a sock over the door, promptly adopting the practice himself. The episode also marks Mark and Amber's first intimate encounter.
The narrator then shifts our focus to "This Missive, This Machination," painting a vivid narrative of the planet Unopa's conquest by the formidable Viltrumites. The vanquished Unopans devised Allen, portrayed by Seth Rogen, as their last hope—a challenge to the Viltrumites and a quest for a worthy adversary. Ironically, the title credits roll as "Allen The Alien," rather than introducing the series as Invincible. Allen alerts the Coalition of Planets about Invincible, who finds the Coalition struggling against the Viltrumite onslaught. Allen champions Mark's cause, arguing fiercely with the council's skepticism towards the Viltrumites. Thaedus harbors suspicions that the council has been infiltrated by Viltrumite spies.
As everyone else seems engrossed in their own affairs, the narrator diverts our attention to Allen's feline-like alien pet. During dinner, Allen is ambushed by three Viltrumites, eager to verify rumors that Omni-Man fathered a child on Earth and deserted his post. Refusing to cooperate, Allen is brutally assaulted, nearly to the point of death, while his girlfriend stands helplessly by. In a drastic move, Thaedus decides to euthanize Allen, ending his life prematurely.
Rudy, now rebranded as Robot, is diligently engaged in an internal battle to eradicate fear from his very circuitry. This transformation does not sit comfortably with Monster Girl, who watches him with a mix of concern and intrigue. Summoning his newly found courage, Rudy asks Monster Girl out to the movies, to his delight, she accepts. Meanwhile, Debbie seeks solace in a support group for the spouses of superheroes, where she encounters Theo (portrayed by Daveed Diggs).
Monster Girl aids Rudy in his first-ever clandestine movie theater experience, complete with his inaugural burger adventure. Elsewhere, Debbie and Theo form a bond over shared cocktails, but their camaraderie is shattered when Debbie reveals that Omni-Man was responsible for the death of Theo's partner, The Green Ghost. It transpires that earlier, William's absence from intimate encounters was due to a simple oversight—he had forgotten to remove the sock serving as a doorstop after his demonstration. Suddenly, the door is knocked upon by Seance Dog—but it is revealed to be Nuolzot in disguise, seeking Invincible under the guise of 'Mark.' Nuolzot, a shape-shifting entity, pleads for Mark's assistance in saving his people from impending meteor showers. Despite Cecil's objections, Invincible agrees to lend a hand.
Outside the bar, Debbie decides to unburden her heart to Theo. Theo, furious upon hearing the truth, sternly informs Debbie never to return to the group. As the narrative unfolds, Nuolzot guides Mark to his king—a revelation that leaves Mark stunned: the king is none other than Nolan/Omni-Man, Mark's own father. The episode concludes on a nail-biting cliffhanger, leaving viewers eager for more.
