Time travel is possible not only with the classic "time machine" but by such things as poorly understood magical or alien artifacts, mighty spells, locations which exhibit temporal anomalies, gates, ffme warps, immense psionic powers, traveling cosmic rifts, catastrophic cataclysms, and the manipulations of inscrutable aliens, high-technology civilizations, and super-powerful beings.

Wishes are often used in such ways as to duplicate the effects of time travel. Make sure that these options are used sparingly, so PC's don't keep getting chances to "go back" and redo things they've screwed up.

One thing that time travel adventures should utilize is a sense of history. The past is not interesting if it seems exactly like the "present" your players are used to. GM's should change their style of refereeing. Try to depict the situation to the players in a different way; have NPC's speak with an accent, use unusual words, extra description and so on. Make up some new rules or modify a few of the old ones.

For example, if your players are used to zipping across a settled galaxy, send them back to a time when hyperdrives where cranky and space was mostly unexplored. In a fantasy setting, the party might visit an age where magic was much more powerful than their own.

Throw in an short encounter with a famous historical personage for color. Make reference to important past events in current terms ("The Titanic's sailing today! Don't you wish you could be aboard?"). Let NPCs give the party their own views of the future ("IBM? Don't waste your money on cardpunching machines, sonny. Invest in the railroads," or "Gee, by 1960 there will be world peace and prosperity, and people will take food pills instead of eating.")

A good adventure needs vigorous PC involvement. Maybe they only wanted to be observers, but happenstance might require that the party take action to preserve the timeline. There's always the chance that the PC's mere presence causes trouble. Mistaken identity or an accident can force participation. For example, the party inadvertently prevents a important NPC from doing something he was historically known to accomplish. They must somehow bring about the result, or face a different future.

Adventures

A typical time travel adventure begins when evidence is uncovered that shows someone is meddling in the past. It's up to the party to go back and prevent any harmful interventions. Another scenario is the escape of criminals to past times, where they. must be pursued. In this case the fugitive(s) are less of a threat to the timeline as to the people living there, since they may be reckless in their use of advanced technology and weapons.

A more complex starting point would be an archeological dig which finds something unusual, say, a spaceship in the paleolithic. How did it get there? If the party lacks the means for time travel, there are still plenty of ways for them to visit the past.

An example of this case could begin when the party stumbles across the ruins of an ancient city. They find writings which apparently detail the doom that befell the moldering metropolis. As they struggle to translate them something occurs which thrusts the party back into the past. Suddenly they are back in the now-thriving city, just before it is to be destroyed!

This scenario can work for a fantasy, horror, or SF type game. It provides a sense of urgency which is necessary, since characters who are able to travel across the centuries may feel that they "have all the time in the world". Perhaps by having a portal closing on their chance to return can keep things moving.

Maybe the party finds a special locale, like a megalithic stone circle or transdimensional tavern that enables them to enter into other eras. Or if they come across time travel experiments by outsiders, they may be forced to another age because "they know too much."

A friendly wizard or govemment agents can approach the party to help with a rescue mission. The PC's have to save some NPC's lost in another time before they precipitate a disaster. Some time travel agencies recruit agents from many different eras. Or the PCs can simply be picked up by curious travelers and taken along on their journeys, too.

Time Intervention - Laws Of Time

Time intervention is the act of attempting to change the present by manipulating the past. In many cases the party's goal is to prevent manipulation by troublemakers. It is subject to the principles of time travel, also known as the Laws of Time, which are covered in "Just a Matter of Time" in issue #12 of SHADIS, but I'll go over the high points again.

The first Law (the "grandfather" paradox) prevents characters from interfering in their own past existence. Causality requires that such actions simply cannot happen-- but, of course, there are always exceptions.

There are two main currents of thought in science fiction about the effects of time travel. The first is that every action at every moment, no matter how trivial-seeming, is of critical importance, and minor changes could create an entire new reality.

The second holds that time is like a vast river where individual actions are like pebbles thrown in; they may make ripples but the course of the river remains unchanged. However, there may be "choke points" (temporal nexuses) where it is possible to change the flow of the ever.

Temporal Nexuses

Temporal nexuses, or T-junctions, are places where the river is shallow and more easily diverted. As with any major project, the proper engineering (i.e., historical research) must be done so that the river of time (the timestream or timeline) is deflected onto the desired path.

The second theory is more suited to a role-playing game and the first theory should only be brought up when time traveling characters are becoming over involved in time intervention. In other words, time-traveling PC's should be allowed to make necessary interventions but should otherwise avoid unintended side effects.

It should be clear that by the First Law of Time, travelers get only one chance to go back and intervene in a particular period. If something stops them, then they may try to go to another hme and try a different intervenffon, but things begin to get much more complicated and failure is likely.

Items cannot be moved from one era to another provided that they have a history fixed in the timeline. In this case, history means that the item has been noticed by someone or its presence has an appreciable effect on future history.

There is no reason why the GM can't allow travelers to bring back inconsequential items, although they might be subject to aging effects. It may be possible to recover certain historical objects provided they are replaced with adequate forgeries, and no one notices the switch. Things that have mysteriously disappeared in the past may well have been snatched up by time travelers (seen the crew of the Marie Celeste, anyone?).

The Other Time Travelers

If the PC's can travel in time, then there's no doubt that others can, too. This opens the possibility of interactions with visitors from other times, particularly more advanced periods, i.e., the future).

However, time travelers nominally want to remain inconspicuous and avoid interference in the past, and they usually have the means to do so. The party may not even realize that they've had a time traveler encounter. It's possible that the travelers may give them some useful bit of information about something that's going to happen, if they're not saddled with a non-interference rule.

Getting out of Hand

This is one area where the GM has the edge on the players, because travelers from the future can be considered to already know what's in store for the party, aside from being much better equipped. This is very useful when the party gets out of hand.

GM: Ok, you've defeated the guards and have entered the secret cavern. Ahead you see a shiny metal sphere with a lot of wires attached to it.

First Player: It's the Nazis' experimental A-bomb!

Second Player: We made it just in time! That V-2 rocket outside is aimed for London.

GM: So you set your demolitions to collapse the cave?

Third Player: Hey I've got a better idea. Let's take the bomb and drop it on Moscow. That oughta eliminate a lot of grief in the coming years.

Other Players: Yeah!

GM: Uh, ok. Suddenly you see an old man in a battered coat standing by the bomb.

First Player: Where he'd come from?

GM: You didn't see him come from anywhere. He says "I wouldn't do that if I were you."

Third Player: Oh yeah! How'd you like to eat a plasma burst, fellah?

GM (as old man): "I think you'll find your weapons and time travel gear has been deactivated."

Players (checking): Ok, well, maybe you're right.

GM (as old man): "How kind of you to agree. By the way would you like a lift back to your own century?"

Civilizations--Chronotechnology (CT) Levels

The following is a overview of time travel technology available in a campaign with a semi-historical basis. This infommation is for the GM, as the PCs won't have any knowledge of technologies more advanced than their own. High technology does not automafically mean time travel, but it helps. It is certainly possible to have a very advanced galaxy-spanning civilization that has no knowledge of time travel, while there may be a culture of rather backward beings who can travel through some innate or magical means.

Level 0 civilizations make up the vast majority of those encountered and are probably the safest to visit. Travelers are seen simply as strangers who seem a bit peculiar. Level 1 or higher cultures, because of their own temporal expertise, become very wary of travelers and often take direct action to control, limit, or capture them.

CT LEVEL 0: Time travel is almost unknown at this level of chronotechnology, and most people don't believe in it. The period ranges from the most distant past (induding medieval- fantasy settings) to so me time between the 19th to 21st centuries (and much further, until time travel is invented). It is also the level where most time intervention occurs.

Temporal voyaging is impossible aside from the effects of a few rare artifacts, singular anomalies or the actions of future visitors. Aside from direct manipulafions, the greatest danger to this era comes from items left behind by level 1 travelers including weapons, chronogear, supply caches, remote surveillance devices, and observation stations.

CT LEVEL 1: Basic time travel becomes possible at level 1. Usually, it results from the efforts of crackpot/genius inventors or misguided government experiments. The equipment is primitive, notoriously unreliable, and accidents are common. One-shot timecans, time projectors with limited range and duration, one-way portals and oddball homemade vehicles (got a DeLorean, anyone?) are all methods utilized. Timescanners (devices which can see into different times) and timescoops (which can pull items out of other times) are also feasible, but most other types of chronotechnology are almost nonexistent. Time theory is virtually unknown, leading to possible disrupfion of the timestream by careless visitors.

Travelers from this era are typically lone adventurers, cranks, and fanatics, and more organized groups of scientists, explorers, and military personnel. They are equipped with anything from obsolete firearms (Victorian Age) to 20th century conventional weapons, but little else.

This period comes to an end when technology advances, and a more centralized group becomes responsible for time travel.

CT LEVEL 2: This is the level where the characters based in Jolly's campaign probably come from. Time-travel is based on projectors or other well defended fixed installations like gates or tunnels. It is usually reliable, although the theory behind it is not always fully understood. Level 2 time travel begins to become available in the distant future.

Personal equipment is well-developed, although it tend to be bulky. Agents are skilled in combat and use of scanning devices to detect temporal fluxes. The agencies are typical of secret government agencies; bureaucratic, with lots of money, but technical and personal difficulties limit the number of people they can send into the past.

Level 2 agencies are mostly involved in suppressing time-terrorists and clearing up the messes left by level 1 travelers. In some cases several rival time agencies compete b adjust the time-lines in their favor, often causing further temporal disruptions. Although well-meaning, level 2 agencies may sometimes cause more harm than good in their manipulations of time.

CT LEVEL 3: This level is characterized by a time police or patrol who possess efficient time vehicles, and a network of agents throughout the time lines, with numerous bases and stations. They are capable of erecting time barriers effective against low-level equipment, and thus remain undetectable to them.

They're often involved in sophisticated actions to repair the fabric of time, but can sometimes be found fighting a time war against highly organized cliques, who are intent on changing the past on a massive scale. Level 3 agencies normally do not cause temporal dislocations, but they are not perfect, and it does happen. The specialize in probing the most capable agents possible, and keeping overhead and administration support to a minimum.

Level 3 technology is found in the distant future. Equipment includes energy weapons and advanced time devices, but even more important is the special training agents receive which allows them to effectively pose as natives of any era, learn quickly, competently operate and repair their gear, and use numerous combat skills. Sophisticated implants and psycho-conditioning are also utilized.

At the end of this period level 3 personnel may become so advanced that they may be difficult to communicate with.

CT LEVEL 4: From the very distant future, this represents the most advanced time-travelling culture. Although they may be highly evolved and time-sensitive, Level 4 travelers usually appear as ordinary humans to avoid notice.

They are master technicians and historians, and have an immense storehouse of knowledge, but their greatest asset is the ability to accurately predict what the actions of their adversaries will be, and take steps beforehand to forestall them. They are capable of impressive mental and physical feats.

Level 4 societies have a deep understanding of time theory and applications and can manipulate time at will, being able to "bend" the Laws of time if necessary. Usually they prefer not to interfere in the past, but continually observe the timestreams for major dislocations.

Some groups are more active, making many subtle interventions. This is generally done by a few independent but highly skilled agents. Control of time travel is an intrinsic part of this society's government, and there are no separate time agencies. Level 4 groups make few errors, but when they do, the scene is not pretty.

Renegades from level 4 are extremely dangerous but fortunately are very rare.

Level 4 travelers possess an exceptional array of compact space/time vehicles and chronoequipment. Their base/ship/homeworld is protected by an impenetrable time shield.

More Time Travelers

Introduction
Encounters
Characters