The opening episode of The Mighty Nein unfolds with a somber ritual. A man plunges his dagger into his suffering wife's heart, hoping for a reunion in the afterlife as her soul is consumed by a beckoning light. The priestesses, alarmed by a deafening clamor, call for guards to shield the beacon. Two of them hustle it to safety, sealing themselves inside with it. But their foes have already outmaneuvered them.
A thief materializes behind an unsuspecting guard, swiftly dispatches him with a silky blade. The same fate awaits the other guard before they can even register a thought. Two more thieves, initially shrouded in invisibility, make their presence known in the room, stealing the beacon. They are Eadwulf, Astrid, and Dain, each skilled in their craft.
As they blow up the entrance to lure soldiers into their path, they nimbly evade attacks and defeat most of them with ease. Drain is hit by an arrow but brushes it off nonchalantly, opening a portal to safety moments later. Once they've escaped, Astrid and Eadwulf scout for their steeds while Drain remains to guard the beacon. But she realizes too late that their adversaries, the Kryn, have already reached their destination. Drain rushes to them, urging his comrades to flee as an explosion shatters the place.
Elsewhere, Caleb, looking haggard and weary, is jostled by a group of teenagers. As he collapses to the ground, he slathers mud on his face and scares them off with a pretended incantation. His attempts to break into a nearby shop prove futile, drawing unwanted attention. To make matters worse, a goblin steals his pouch as he tries to hide in an alley.
The goblin has the upper hand due to her agility and speed, but Caleb manages to corner her nonetheless. Despite his efforts, he can't seem to dislodge her. So, Caleb grabs her leg and pleads with her to return it, realizing its importance to him.
In the end, Nott, the goblin, relents, her potential becoming a key to his predicament. Should he provide her with a nectar of refreshment, she promises to aid him in his quest to break into the shop's confines.
Elsewhere, Trent Ikithon, a formidable archmage, imparts a lesson in fear to his students, a practice that verges on torture, a pastime he clearly relishes. However, the King, Dwendal, summons him for a parley. The kingdom has been embroiled in a protracted cold war with the Kryn, and recent news has sent tensions spiraling. The previous day, thieves had made off with the Luxon beacon, a sacred relic revered by their faith. The Bright Queen, their empress, suspects Dwendal of complicity and orders preparations for war.
Concurrently, two investigators delve into the mystery of the beacon's disappearance and the thieves' identity. Beauregard detects oddities around the scene—people and horses appearing more decomposed than they should be, along with sets of footprints that defy explanation.
Yet, her partner, Ruzimir, carries a profound bias against the Kryn, clouding his judgment. He overlooks numerous clues and arrives at a conclusion that falls short of satisfaction. But Beauregard sees more clearly and discovers remnants of a struggle, including a peculiar green crystal.
Later, she endeavors to convince her mentor, Zenoth, of her findings and presents him with the gem. She demonstrates its ability to amplify magic, which may account for some of the phenomena witnessed at the scene.
However, he is not satisfied with her work, accusing her of being too egotistical and unworthy of the Cobalt Soul monk's mantle. Displeased, he sends her away to ponder her actions.
The thrilling episode returns to Caleb, who cunningly feigns呕吐on the street to distract attention from Nott. To his delight, the plan succeeds, and they slip into the shop unnoticed. Nott realizes they've stumbled upon a pet shop and is puzzled by Caleb's presence there. Nonetheless, her focus remains on finding more coins, until a more sinister discovery awaits her: a poster declaring Caleb wanted for murder.
Meanwhile, Caleb tinkers with a cage, attempting to soothe the enraged animal within. A seemingly furious bat lunges at him, prompting him to swiftly shut the cage and inform Nott that their time there is done. The shop owner arrives just in time, but they evade him, causing a commotion.
Beau tailors Zenoth around town and witnesses him entering a location where dwarves are crafting the green crystal she had discovered. The man delivers the crystals to Owelia, who works for Ikithon, revealing their complicity in fomenting war.
Beau shifts her target to Owelia, but it's a misstep. The warrior tricks and attacks her unexpectedly. Although Beau appears to be a match for her at first, Owelia gains the upper hand with magic and appears to slay her. Or so she thinks.
Dairon, another Cobalt Soul, saves Beau and reveals the conspiracy within the Empire. Seeing her mentor betray their organization makes Beau feel worthless, but Dairon sees it as an advantage—no one will expect her.
As one alliance is forged, another may be teetering on the brink of destruction. After downing all her booze, Nott contemplates attacking Caleb for the bounty on his head. However, his magical ritual changes her mind.
As she tries to sneak up on him, he summons a cat he calls "old friend," embraces it, and then it vanishes into thin air, leaving both Caleb and Nott in tears. Caleb's wizardly prowess captivates Nott, and he suggests they stick together. If he procures more alcohol for her, she'll help him acquire purer materials for his magic. They decide to visit a carnival next, where they might find valuable items.
Before departing, Nott inquires about how Caleb lost his magic. He claims someone stole it, but he hasn't killed them...yet.
Far away, Ikithon meets with Eadwulf, Astrid, and Dain, who is dying after being hit by the explosion. They reveal that they possess the beacon, which drains Dain's life after the archmage mercifully ends his suffering. But Ikithon is unconcerned as he sees the beacon as the key to their ultimate goal.
A strange force approaches their war as a warrior effortlessly slices through soldiers while searching for the beacon.
