When in Rome — Wayne Mansfield

The year is 2029, and Marco has been working on a time travel machine. His friend Derek suggests they try it out, but even as he programs the machine for ancient Rome, he doesn't think it'll work.

The next thing he knows, he's picked up by a slave trader and taken to a marketplace in ancient Rome. Potential buyers poke and prod him, examining the merchandise from every angle, yet bidding is slow. After the auctioneer, who is keen for a sale, announces that Derek is a virgin, hands shoot into the air. All Derek can do is watch and pray whoever buys him is kind and halfway good-looking.

His prayers are soon answered, though he is informed on the way back to his new master's villa that he is to be put to work that very night. Far from home and alone in a strange, ancient world, he does the best he can. Neither he nor his friends had talked about getting him home to 2029 again.