Inside a home off Richmond Road in Lexington stands a portal. It's a gate to medieval times. To pandemics. To battles. To ancient religions.

Working in their basement, homeowners Michael and Pang Hartman have crafted and continue to shape a fantasy realm that 5,000 people worldwide inhabit.

It's Threshold, a 13-year-old, text-only, role-playing computer game, and it's about to have a sequel.

The Hartmans and the 11 freelance staffers of their company, Frogdice, have built Primordiax, a new game launching in the next month that continues the fantasy world of Threshold.

Threshold grew out of Michael Hartman's time spent playing "multi-user dungeon" computer games, or MUDs. The games, which began in the 1970s with the forerunners of personal computers, require players to interact with each other by typing commands.

Unlike today's video games, they have no graphics. Just words.

Hartman began developing Threshold about 1994 while he was in law school at the University of Georgia.

"In the classic entrepreneurial spirit, I thought I could build a better mousetrap," he said.

He taught himself computer programming and soon found that he liked it much more than the law. "I eventually just said that I really hate being a lawyer, and I really love making games," he said.

By 1996, he was full-time in the video game business. And while work on many of today's video games end right as they hit store shelves, Hartman, 37, and his wife, Pang, 33, have spent years keeping Threshold fresh.

The game contains the elements of any standard role-playing game: quests, leveling up characters, purchasing goods and more. Players join guilds, or clans, and try to become the most influential. They also take part in a religion system.

"We're always adding more content," Michael Hartman said.

A recent example was an invasion of a town near one of the world's capital cities."The players have to figure out why it's being invaded and whether they would help," he said. "What kind of help they give will change how we react.

"We try to keep the world really dynamic. It's another thing you can do in text that's really hard to do in graphics; we let the players have a real effect on the world."

One rule that sets Threshold and soon Primordiax apart from other computer role-playing games is that players must stay in character.

"You can't talk out of character. You can't say, 'How about those Cats?'" said Hartman. "I think it raises the maturity level and creates kind of a tighter community."

The games also provide a far more complex experience than typical graphics-intensive games, said player Meghan O'Malley, who is a student at Michigan State University.

"When I explain to friends that I play a 'text-based game' and get the blank stares, I always describe it as a sort of book that you're writing with other people," O'Malley said. "You get to read and interact with what other people have come up with, and you get to add your own ideas to the world, influencing what happens."

O'Malley, who plays graphical RPGs like World of Warcraft, said her first love has always been reading and her "very active imagination" makes her prefer "picturing things in my imagination rather than looking at someone else's interpretation."

The characters also present a level of complexity not in other games.

Take the character, for instance, of Brownell Combs, who lives in Fairfax, Va., but began playing shortly after graduating from Centre College in Danville in 1997.

In the game, he's a "justicar," basically a mix between a police officer and criminal prosecutor.

"In other games, you get your equipment and you go kill things," he said. "As a justicar, I get to write legal briefs. It's all based on precedent. You would go back and review the previous cases in Threshold and cite old case law to support your current position."

It's a complexity that plays to the game's demographics. The average age of a player is 33, said Pang Hartman, and the company doesn't allow people younger than 18 to play.

"It's not because there's any adult content," Michael Hartman said. "It's just that grown-ups like that the fact that they can play with other grown-ups."

Game mechanics

For years, playing the game cost $50 annually, but three years ago, the Hartmans dropped the fee.

Since then, the subscriber base of 3,500 has grown by about 500 a year.

"For a game that's 13 years old to gain subscribers, that's huge," Michael Hartman said.

Running the game, though, is the couple's only job, and they make a living at it by charging for certain game features. Players can pay for more storage of virtual items or to buy in-game money.

It's a way, the couple say, that people without a lot of time can still acquire the resources to compete against other players.

About 80 percent of players pay, and the average amount spent is somewhere around $250 annually, the Hartmans said.

"There are people who pay over a thousand dollars a year," Michael Hartman said.

And the subscribers wind up willing to pay for far more than just in-game features. The game has become such a community that its fans have annual conventions.

The past five have been in Lexington with about 50 or so people heading to the Bluegrass each year.

The gathering in 2006 was more than just a fun way to meet fellow players for Jodi Witherspoon.

Earlier that year, Witherspoon confided to her online friends that she was in a troubling situation at home.

At their urging, she said, she and her four kids left the home "with nothing but the clothes on our backs."

"When they became aware of my situation through our member forums, my entire family was blessed with everything from toys to books, even to a $100 gift certificate to Amazon," Witherspoon said.

She wound up attending the year's convention and "got to meet the wonderful people who had always been there for me."

You would need look no further than the Hartmans to see other examples of the community. They met in 1998 while playing the game and married three years later. Now they're the parents of two daughters, ages 3 and 7.

They moved to Lexington in 2004 to to be closer to Pang's parents, who live in Campbellsville.

The world of 'Primordiax'

Within the next several weeks, the Hartmans expect to launch Primordiax, which recently completed its third phase of testing.

The game is similar to Threshold in many respects. It is set in the same fictional world, just 4,000 years later.

But it introduces a first: graphics.

Primordiax includes pictures of characters. It also has been programmed in Flash, unlike the command line interface of Threshold.

With goals of bringing on more Flash programmers and artists, the Hartmans are looking for outside investors and are "getting close with a couple of different people."

"We're pretty confident we'll find someone," Michael Hartman said. "We're just looking for the right fit."

As for the game's story, it follows on a long-held myth in the Threshold world that "there will eventually be a final battle," he said.

By the time of Primordiax, the battle — called the "Sundering" — has happened, "and it almost destroyed the world."

After the climactic battle, the world's creator deity returned, threw out the old gods and installed new ones who are less conflict-oriented.

The couple have already been working on time-travel tales involving the two games, he said, to keep both fresh for years to come.

They expect Primordiax to eventually have 5,000 to 10,000 players and think many people will play both.

They've also been expanding in recent months to develop casual Flash-based games, and they intend to continue producing a variety of online games.

"Our company motto is 'Our world, your imagination,'" Michael Hartman said. "We have an internal mantra, too, that is: 'Great games we would play.' And that's pretty much our philosophy."