The world has not been the same since the outbreak and ending of World War 3 in the same year, 2079, when the "Developing Countries" in Africa and Asia finally rebelled against the exploitation by the western "industrial countries". A massive launching of nuclear and "space" weapons on the side of the latter not only quenched the rebellion, it also caused considerable and irrevocable damage to the very structure of Universe.
Huge rifts suddenly appeared in the Time Warp, and there are no more just the usual 3 dimensions to the world as we knew it. A 4th Dimension has occurred - the "Time-space Dimension", which makes it possible to move between one time period and another in a split second.
While these phenomena were not unknown to the scientists back in the 1980s, who used to call them "Black Holes", they used to be extremely rare and confined to space. Now they are becoming increasingly frequent, and they can occur almost anywhere on earth. The primitive and superstitious people in the early ages shun them like death itself, believing them to be caused by evil sorcery and witchcraft. As you walk peacefully down a country lane, you may suddenly step into one of these rifts in the Time Warp - and suddenly you find yourself in a quite different time period, where the surroundings are totally different and possibly hostile too.
The locals call them "Time Traps", and have learned how to avoid them. Indeed Man - the most adaptable of all creatures - has even learned how to exploit them. Ruthless adventurers use them for their own shady means, hopping from Time to Time, to ransack and plunder. There is also quite a considerable Tourist Industry developing around them, offering the customers "Travels Through Time" and "Time Safaris", with or without guides and professional bodyguards. The resourceful tourist can hire himself some armed bodyguards, and make the travels in reasonable safety, while the less well to do will have to venture the exploit on their own.
Needless to say the Travel Companies take no responsibility whatsoever, lest you should happen to get killed during the Time travels. Needless to say such events occur pretty frequently too, since quite a few of the places you land in are all but peaceful. However death isn’t such a big deal anymore because of the time rifts - you can always be resurrected at a time before the unfortunate event occurred, and thus return to life again without much ado. (Needless to say there are people who exploit that fact too, and being resurrected after getting killed will cost you a neat sum, that will be deducted from the experience points you gathered. If you want your corpse and equipment retrieved too, it is going to cost you quite a bit extra).
For some reason the Rifts in the Time Warp seem to be more frequent than otherwise in a few places on earth, and one of these concentrations of "Time Traps" is right at the place called "Recall". One of the larger Travelling Companies - (run by Molly & Peace Travelling and Adventure Co. Inc.) - has set up a Travel Agency at that place. There is a Time Guardian in a room upstairs from Recall, who will on request send you to any of the 4 most popular time periods - PreHistoric, Medieval, OldWest and Future, and you can in most cases return to that place too simply by reciting a "Recall" scroll.
You can gather gold, equipment and experience in all 4 Dimensions, but if you want to avoid being gawked at by the locals, maybe you’d prefer to attain your equipment from that Dimensions solely? Even though it isn’t forbidden to bring modern equipment to the earlier time periods, a laser gun in medieval time will make you a bit conspicuous, and most travelers like to melt into the surroundings. (You know, there is nothing a Tourist fears more than looking like a Tourist!)
So maybe the 4th dimension isn’t such a great catastrophe after all. Sure enough, the first time you step into a Time Trap can be a shattering experience. But once you get used to it, you too may develop into one of those successful Time Hoppers, who have gathered vast experience and fortunes from their adventures, and who are now being regarded as "Gods" in most time periods - people like the mighty Directors Shorty, Kalten, Molly and Mordecai. Who knows - one day you may even reach immortality yourself...