In "Invincible" Issue #55, the plot unfolds dramatically within the confines of a Viltrumite prison, where both Allen the Alien and Nolan Grayson (Omni-Man) are held captive. The narrative starts with Allen, who has intentionally allowed himself to be captured, awaiting sentencing. He uses his telepathic abilities to communicate with Nolan, sharing his escape plans, personal tidbits about his son, and forbidden love with Telia. Through these exchanges, the two form a bond and reminisce about their past battles, unaware of each other’s true identities at the time.
As they converse, an attempt is made on Allen's life by an enslaved alien race using a head-crushing device, which fails spectacularly when the device breaks against Allen's strength. Subsequent efforts with a laser also prove futile, reflecting off him harmlessly. The frustrated aliens eventually give up.
The tension escalates when a Viltrumite arrives to execute Nolan. Forewarned by Nolan, Allen quickly breaks free from his restraints and initiates the breakout plan. He liberates other prisoners, assessing their strength for the upcoming conflict. Among the freed is Battle Beast, who eagerly joins the fray, driven by his insatiable lust for battle.
As Nolan struggles against his Viltrumite assailant, admired by the latter for his past valor, Allen and Battle Beast disrupt the execution—a sacred act in Viltrumite culture. Infuriated, the Viltrumites confront the trio, leading to a fierce skirmish. With Battle Beast relishing his combat against another opponent, Nolan and Allen fight off their captors. Allen, showcasing newfound power, punches a hole in the prison wall, exposing the interior to the vacuum of space, which proves lethal for the non-spacefaring enslaved aliens.
In the heat of battle, Allen and Nolan demonstrate formidable teamwork, combining their strength to gruesomely defeat a Viltrumite by smashing his head, spilling brain matter and eyeballs, a moment that leaves them in shock at the brutal efficacy of their assault. Meanwhile, Battle Beast continues his duel, undisturbed by the chaos around him.
Towards the climax, as the prisoners make their escape, Allen realizes he needs to retrieve his equipment, which holds crucial information on Nolan’s books. Nolan reassures him, revealing the significant fact that there are less than 50 pure-blooded Viltrumites left, a vulnerability that could lead to their eventual downfall.
This breakout is a crucial narrative arc that deepens character relationships, highlights themes of resistance and rebellion, and sets the stage for future conflicts within the "Invincible" universe.