These four paperbacks are separate Delta Green operations, not a single campaign anthology. For a dated 1990s game, The New Age begins in July 1997 and Artifact Zero sends Agents to investigate in fall 1999. Holy War is explicitly set in December 2001. Owlshead Mountain is presented as a companion to the 1990s sourcebook The Conspiracy, but its product description does not give the operation an exact year. Each also offers a different first lead: a defense-linked death, vanishing researchers, missing workers in Vermont, or a ritual murder outside Phoenix.
Choose the operation for the date and investigation you want to run, then check the rules you have. Three listings explicitly name Delta Green: Need to Know as a playable quickstart option; Holy War names Delta Green: The Role-Playing Game but does not expressly address the quickstart. The Conspiracy supplies 1990s setting material, not a stated requirement to buy before any of these scenarios.
Compare the Dates and First Leads
| Operation | Date supported by its listing | Initial investigative target | Listed rules option |
|---|---|---|---|
| The New Age | July 1997 | A strange explosion at a retired Air Force colonel’s home, drawing attention to Enolsis and a crystal Realizer | Agent’s Handbook or Need to Know |
| Artifact Zero | Fall 1999 investigation; discoveries begin in spring 1998 | Researchers disappearing after anomalous finds at a Montana mining site | Delta Green: The Role-Playing Game or the free Need to Know quickstart |
| Owlshead Mountain | No exact operation year stated | Two blasters missing during preparations for Vermont ski slopes, against a history of disappearances and floods | Delta Green: The Role-Playing Game or the free Need to Know quickstart |
| Holy War | December 2001 | Randall Tebbs’s ritualistic murder outside Phoenix, resembling a 1994 Chicago case | Delta Green: The Role-Playing Game; quickstart use not specified |
Those date distinctions matter if your continuing campaign has a fixed calendar. The 1994 Chicago incident in Holy War is a lead into its 2001 case, not the date of the operation. Likewise, Artifact Zero recounts evidence found in 1998 and summer 1999 before its fall 1999 disappearance investigation begins. Owlshead Mountain belongs in the comparison because it is sold as a 1990s-sourcebook companion, but that wording alone cannot establish where it falls between the other three dated stories.
The New Age: a July 1997 Institutional Lead
Delta Green: The New Age (paperback) opens in July 1997. Its fictional religious movement, Enolsis, promotes crystal Realizers. Delta Green initially regards the movement as ordinary grift, until news of an unusual explosion at the home of a retired Air Force colonel changes the picture. The colonel has ties to major defense contractors; the blast leaves him merged with the floor, still holding a Realizer. The advertised questions connect that incident to Enolsis, its leader known as the “Living Power,” and a newly appearing planetoid.
This is the clearest choice here if you need a precisely dated 1997 operation. Its entry point also differs from a straightforward missing-person assignment: the Agents have a disturbing incident associated with someone in the defense world, a movement Delta Green had dismissed, and questions that extend beyond either institution. That makes it a plausible purchase for a campaign already interested in official connections, public reporting, or organizations with carefully managed reputations. The listing poses those connections as mysteries; it does not tell a buyer how they resolve.
The publisher calls it a complete scenario playable with the full rules in the Agent’s Handbook or the quickstart rules in Delta Green: Need to Know. If your group is using the quickstart, this is one of the operations whose own listing explicitly supports that choice. The paperback ships with a free PDF download.
Artifact Zero: a Fall 1999 Investigation with an Earlier Trail
Delta Green: Artifact Zero (paperback) has the most carefully staged timeline of the four descriptions. In spring 1998, a mining company scanning a Montana site for precious metals sees readings that appear to indicate anomalous artifacts at suspicious depths. In summer 1999, university researchers find apparently modern objects there: pieces of machinery, sunglasses, a wristwatch, and a skeleton bearing modern dental work and a surgical pin. The scenario’s premise places them in material buried for five million years. In fall 1999, researchers begin to vanish and Delta Green sends the Agents in.
For campaign placement, spring 1998 is the beginning of the site’s advertised history, not the Agents’ stated arrival. Choose this book if you want a late-1999 investigation in which the team can confront an accumulating record of anomalous finds before facing the disappearances. The description signals horror involving time, rather than a conventional archaeological discovery; its objects and burial claim are elements of the scenario’s fiction. It does not disclose the outcome of the investigation.
The Montana site gives this operation a distinct practical shape. Whereas The New Age starts from a death that raises questions about a movement and defense ties, Artifact Zero starts from a location that has already attracted commercial and academic attention. For example, if your Agents have been following a 1999 campaign calendar, the earlier scans and excavations can serve as dated background while the fall disappearances supply their current assignment. That is a way to use the dates on the product page, not a requirement to run a separate 1998 episode.
The listing expressly permits play with Delta Green: The Role-Playing Game or the free quickstart in Need to Know. It also says the paperback ships with a free PDF download.
Owlshead Mountain: a Vermont Threat Without a Stated Year
Delta Green: Owlshead Mountain (paperback) begins with a local legend. Missing hikers and partying students are jokingly blamed on Cooter McGee, an old moonshiner whose body was never found. But the more immediate history is grimmer: two surveyors disappeared, floods killed more than a dozen searchers, and now two blasters have vanished while preparing a set of ski slopes. Delta Green knows something about the earlier flood threat and sends Agents to confront what is on the mountain.
This is the pick if a continuing game would benefit from a geographically concentrated assignment built around local stories, prior casualties, and a new disappearance. The advertised opening gives the team more than folklore to investigate: the vanished workers and the surveyors provide distinct incidents, while Delta Green’s knowledge of the floods makes its interest in the site deliberate. The blurb leaves open whether the legend explains anything.
Do not assign it a particular 1990s year on the strength of the listing. The publisher calls it a companion to the 1990s sourcebook The Conspiracy, but gives no exact year for the present action. If precise continuity is essential—for example, if a campaign must fit between July 1997 and fall 1999—check the scenario itself before committing to that slot. If your calendar is flexible, the public description is enough to compare its Vermont investigation with the dated alternatives without pretending it supplies a date it does not.
Its listing explicitly supports either Delta Green: The Role-Playing Game or the free Need to Know quickstart. The paperback ships with a free PDF download.
Holy War: December 2001, Not a 1990s Operation
Delta Green: Holy War (paperback) is set in December 2001, amid the aftermath of 9/11. The initial case is the ritualistic killing of Randall Tebbs outside Phoenix, Arizona. Delta Green sees a resemblance to a mass murder in Chicago in 1994 and already has a suspect in mind. Shortly after the Agents arrive, the suspect destroys himself in an explosion; the description then promises a victim speaking with the voice of a god and a trail leading across the country to New York, toward a clash involving the Great Old Ones.
Buy this one for a campaign ready to reach 2001, or for a separately dated operation that begins with a murder inquiry and expands beyond its Arizona starting point. The 1994 connection offers historical context for Delta Green’s suspicion, but it does not make Holy War interchangeable with the two explicitly dated 1990s investigations. Its advertised travel toward New York also sets it apart from Artifact Zero’s Montana site and Owlshead Mountain’s Vermont mountain. These are differences in the published premises, not promises about play length or difficulty.
The rules distinction is worth checking before purchase if you have only a quickstart. The Holy War listing says it can be played with Delta Green: The Role-Playing Game; unlike the other three operation listings, it does not explicitly name Need to Know. That absence does not establish incompatibility, but it gives quickstart-only groups less direct assurance. The paperback ships with a free PDF download.
Where the Conspiracy Fits—and What to Buy First
Delta Green: The Conspiracy (hardback) is a 1990s sourcebook for the role-playing game, rather than a fifth stand-alone operation or the core rules named in the scenario listings. It is an updated and rearranged version of the original 1997 Delta Green sourcebook, with new art and graphic design and new appendices. Its contents include Agents and Friendlies, campaign and Delta Green material, groups such as Majestic, the Karotechia, Saucerwatch and the Fate, plus sections on 1990s federal agencies, security classifications, manuscripts, and rituals. The hardback ships with a free PDF.
That content is most relevant when you want the operations to feel connected to a wider 1990s Delta Green campaign. It can provide period and organizational context around a 1997 or 1999 scenario, and the operation listings recommend it as a companion. They do not say it must be owned to run those scenarios. Nor does a 1990s companion label override Holy War’s explicit December 2001 date or supply Owlshead Mountain with a missing one.
A practical buying sequence is therefore conditional. If you already have full Delta Green rules and want a single dated 1990s case, start with The New Age for July 1997 or Artifact Zero for fall 1999; choose by whether the defense-linked blast or the Montana research site better fits your campaign. If you have only Need to Know, those two and Owlshead Mountain explicitly list quickstart play, while Holy War warrants a rules check. If your next session should begin with missing workers and mountain folklore, consider Owlshead Mountain while keeping its year open. Save Holy War for a game that can accommodate its 2001 setting. Add The Conspiracy when you want its broader period material, rather than assuming every operation requires another book.
