Who What and When are We?

Bob Farmer has hit the jackpot. In a flash he got a highly-paid position with a prestigious research company and found a new beautiful and incredibly sensual girlfriend Zara. Bob's life suddenly seemed too good to be true. As it turns out - it was.When he and Zara went on what was supposed to be a one-night camping trip his perfect world disintegrated - a rift in the space-time continuum opened they were thrust tens of thousands of years into the past. From there they bounced back and forth from the past to the future and in the process encountered cavemen early pioneer settlers benign aliens hostile aliens bootleggers the KKK and disco dancing. The only good thing in Bob's mind at least was that despite the dangerous situations they found themselves in Zara's appetite for sex never diminished.When he and Zara finally returned to their own time Bob figured nothing else could go wrong. That's when he learned however that Zara was not what she seemed to be. The truth was that she was an alien who required a lot of sex to build a weapon and that weapon just happened to be Bob himself.