Pandemic: Legacy, one of last year's best board games, is getting a second season, co-designer Rob Daviau tells Polygon. What exactly is inside the box he won't say, and that's part of the fun.

The original game has been on sale for about six months, receiving praise from our website as well as Kotaku, Wired and our friends across the pond at Shut Up & Sit Down. The game, which pits players against a set of evolving viruses over an experience that lasts 12 in-game months, is even being gobbled up by actual epidemiologists at Georgetown University and technologists at the United States Agency for International Development — essentially real-life analogues to the characters in the game.

The original game was subtitled "Season 1," but so far a second season hasn't been confirmed. During a recent interview, Polygon broached the topic and he admitted that he's already been working on Season 2.

"The original has done well," Daviau said last week by telephone. "In half an hour I have a continuing call with [co-designer] Matt Leacock, because we’re working away on 'Season 2.' When we say 'let’s do one,' the time until it’s in your hands is about 24 months."

Daviau said he and Leacock have been working on season two since before the release of season one, which would put it about a year away from being finished.

"We started it before this one came out. But we are not done, and when we are done I will leave it up to the publisher to say when they will choose to put it out."

The original Pandemic: Legacy was published in the U.S. by Z-Man Games.

Update: Rob Daviau reached out after the publication of this article to say that his math had been a little off. Instead of 18 months, the full development cycle of Season 2 will be more like 24 months. We've amended the article above to show that.