Black Mesa: Ocean Death

In 2003, the USNS Eidolon Horizon, a secretive DOE research vessel operated with Black Mesa, conducted a deep-sea experiment studying unstable Xen dimensional portals in the North Atlantic. During a critical test, containment failed catastrophically, opening multiple portals throughout the ship. Hostile Xen creatures—Vortigaunts, Houndeyes, Armored Headcrabs, Graulox, and Bullsquids—flooded the vessel. Power failed, communications cut out, and the ship descended into darkness. Crew members were overwhelmed or transformed into violent Headcrab Zombies, many still wearing torn security vests or lab coats. A fragmented distress signal prompted the USS Bataan to deploy a 20-man Hazardous Environment Combine Unit (HECU) via AAVP-7A1 to board the Eidolon Horizon. The HECU’s mission was to secure survivors, recover vital research data, and eliminate alien threats. Inside the ship, the team faced relentless Xen attacks and environmental hazards like radiation leaks and unstable portal energies. The Eidolon Horizon had become a nightmarish battleground—an oceanic tomb where alien horrors and failing containment systems tested every ounce of the HECU’s skill and resolve.