Overview:
In the bustling Orion Arm, where interstellar trade fuels galactic prosperity, a fanatical cult worshiping a sentient black hole—known as the Void Cult—has seized the Nexus-9 Hyperspace Relay Station, a critical hub for faster-than-light travel. Their ritual to “commune” with the singularity threatens to destabilize the relay, risking the collapse of trade routes and plunging entire sectors into chaos. The powerful Orion Trade Consortium hires the player characters (PCs)—a diverse crew of mercenaries, diplomats, or rogue scientists—to infiltrate the station, neutralize the cult, and prevent catastrophe. What begins as a straightforward mission becomes a web of cosmic mysteries, corporate betrayal, and moral quandaries, with the PCs’ choices shaping the fate of the Arm.

Setting:
Nexus-9 is a massive, ring-shaped station orbiting a stable hyperspace node, its sleek corridors and control hubs now defiled by the cult’s eerie sigils and pulsating altars. The station’s advanced systems—grav-generators, defense grids, and comms arrays—are partially under cult control, creating a claustrophobic battlefield. Beyond its view ports loom the faint distortion of the black hole Erythros, a distant singularity the cult reveres as divine. The Orion Arm itself is a vibrant tapestry of megacorporations, alien enclaves, and independent colonies, all reliant on Nexus-9’s relays for commerce and communication, making the stakes galactic in scope.

Adventure Structure:

1. The Hook (Introduction):
   The Orion Trade Consortium contacts the PCs while docked at a nearby trade hub, perhaps a neon-lit megastation or a gritty frontier port. Their fixer, a polished exec named Vara Solis, offers a lucrative contract: infiltrate Nexus-9, rescue any hostages (including diplomats key to trade talks), and stop the Void Cult’s ritual before it catastrophically damages the relay’s core. Initial intel suggests the cult, led by the charismatic Prophetess Zarael, has barricaded the station and hacked its defenses. The PCs must reach Nexus-9 via a stealth shuttle, evading cult-patrolled debris fields and automated turrets.
2. Infiltrating Nexus-9 (Stealth and Exploration):
   Breaching the station is no small feat. The cult has rigged Nexus-9 with traps—motion sensors, EMP mines, and reprogrammed security bots. Key areas include:
   • Docking Bays: Cult enforcers sealed these, requiring hacking or brute force to enter. A failed attempt triggers an alarm, summoning zealots armed with plasma lances.
   • Crew Quarters: Members converted the quarters into cult shrines, littered with journals hinting at Zarael’s visions of Erythros “speaking” to her. Some crew resisted, leaving caches of weapons or bypass codes.
   • Grav-Core: The station’s heart, where gravitational anomalies (shifting floors, floating debris) complicate movement. Here, the cult performs its ritual, its machinery humming with unnatural energy.
     Early encounters test stealth and diplomacy: the PCs might bribe a defecting cultist, sneak past patrols, or ambush a zealot squad to secure access cards.
3. The Cult’s Grip (Combat and Intrigue):
   Inside, the PCs face the cult’s hierarchy—fanatical acolytes, psionic “Seers” channeling Erythros’s influence, and elite Void Wardens wielding gravitic weapons. The cult’s ritual is destabilizing the relay, causing tremors and temporal glitches (e.g., brief time-loops or distorted perceptions). Key challenges include:
   • Hostage Crisis: Diplomats from rival factions (e.g., the human Concord, the insectoid Zykari Collective) are held in a fortified comms hub. Freeing them risks a firefight, and some hostages may be cult sympathizers, sowing distrust.
   • Seer Visions: A captured Seer offers to share Erythros’s “truth” via a psionic link, revealing glimpses of a cosmic intelligence—or a manipulative trap. Accepting risks mental corruption but could yield clues to stopping the ritual.
   • Sabotage: The PCs must disable cult-controlled systems (e.g., power relays feeding the ritual) while fending off waves of zealots. Creative solutions—rerouting plasma conduits, hacking drones—shine here.
4. Unveiling the Conspiracy (Mystery):
   As the PCs delve deeper, they uncover evidence that the Void Cult didn’t act alone. Data pads and intercepted comms suggest the Consortium—or a rogue exec within it—funded Zarael’s rise to destabilize rival corporations or seize Nexus-9 for monopolistic control. Other possibilities include:
   • Zykari Involvement: The insectoid faction seeks to weaken human dominance by disrupting trade.
   • A Sense of Urgency: The unstable gravity fields are sending tremors throughout the station, becoming progressively worse as the adventure progresses with a major quake occurring just before the ritual completes.
   • Ancient Tech: The cult’s ritual uses outlawed tech linked to Erythros, hinting at a precursor civilization that “fed” the black hole.
     The PCs must decide whether to confront Vara Solis, leak the truth to the hostages’ factions, or keep the intel for leverage. Rival agents—a corporate strike team or Zykari infiltrators—may board Nexus-9, forcing uneasy alliances or betrayals.
5. Climax: The Ritual’s Edge:
   The PCs reach the grav-core, where Zarael conducts the ritual atop a pulsating altar, surrounded by chanting Seers and a swirling vortex of gravitic energy. The relay’s core is moments from overload, threatening to rip Nexus-9 apart. Options include:
   • Direct Assault: Storm the altar, battling Zarael (a psionic powerhouse) and her Void Wardens. Disrupting the ritual requires destroying the altar or rerouting its energy, risking a core meltdown.
   • Negotiation: Zarael claims Erythros offers salvation, not destruction. Convincing her to stop requires navigating her zeal and proving the ritual’s danger (e.g., via hacked data or Seer visions). Success might save lives but let her escape.
   • Sacrifice: A PC or ally could interface with the altar’s tech to shut it down, risking death or absorption into Erythros’s consciousness. This yields a bittersweet victory with cosmic implications.

The climax ends with a desperate escape as Nexus-9 quakes—shuttles malfunction, corridors collapse, and rival ships close in to “secure” the station.

1. Resolution and Aftermath:
   If the PCs succeed, Nexus-9 is saved, restoring trade and earning Consortium favor (or suspicion if they exposed the conspiracy). Failure sees the relay collapse, triggering economic chaos and factional wars. Possible outcomes:
   • Exposing the Consortium’s role sparks galactic outrage, boosting the PCs’ rep as whistleblowers or painting them as traitors.
   • Keeping the cult’s tech (e.g., gravitic weapons, psionic amplifiers) makes the PCs targets of spies and bounty hunters.
   • Zarael’s fate—captured, dead, or fled—sets up future arcs. If Erythros is sentient, its faint “whispers” may haunt a PC’s dreams.
     The adventure closes with the PCs richer (credits, tech, or allies), but the Orion Arm’s stability hangs by a thread, with new contracts or vendettas looming.

Key NPCs:

• Vara Solis: The Consortium fixer, charming but cagey. Her loyalty wavers if the PCs uncover her ties to the cult.
• Prophetess Zarael: A human mystic with glowing eyes, driven by visions of Erythros. Charismatic and ruthless, she’s both foe and potentially an ally.
• Khex-9: A Zykari diplomat-hostage, pragmatic and observant. They offer trade secrets for rescue but may spy for their collective.
• Toren Vahl: A defecting cultist, wracked by guilt. He provides intel on the ritual, but he fears retribution from Seers.

Themes and Tone:
Eclipse of the Void Cult blends space opera’s grandeur with existential dread. The cult’s fervor clashes with the Consortium’s cynicism, while Erythros looms as a cosmic wildcard—a god, an anomaly, or a hoax? The station’s high-tech chaos (grav-shifts, psionic pulses) contrasts with the cult’s primal rituals, creating a tense, cinematic vibe. PCs grapple with questions of faith, greed, and survival, all while racing against a galactic clock.

Game Mechanics (System-Agnostic):

• Skills: Stealth (avoid patrols), Hacking (disable traps), Psionics/Medicine (counter Seer influence), Persuasion (sway NPCs).
• Combat: Zealots use hit-and-run tactics; Seers wield mental attacks; Wardens manipulate gravity.
• Choices: Track decisions (e.g., save hostages, expose Consortium, spare Zarael) for campaign ripples.
• Rewards: Credits, cult tech (risky but powerful), faction alliances, or forbidden Erythros knowledge.

Options:
Shift the conspiracy’s source (Consortium vs. Zykari vs. rogue AI), Zarael’s motives (visionary vs. puppet), or Erythros’s nature (sentient vs. natural). Rival factions boarding Nexus-9 can vary—pirates, rebels, or alien enforcers—keeping each run dynamic. The cult’s tech or Zarael’s escape can seed sequels, from chasing her to battling Erythros’s influence.

This adventure delivers a 2–4 session arc packed with action, intrigue, and cosmic stakes, ideal for a space opera campaign craving high-wire tension and galaxy-altering choices.