(AP) -- For one online game maker, pirates evolved from wizards.

KingsIsle, the maker of a popular multiplayer game for kids, is unveiling its second title, "Pirate 101," on Wednesday. It's a world of floating ships and do-gooder inspired by its other game, "Wizard 101."

The games are free to play. KingIsle Entertainment, which is based in Plano, Texas, makes money by charging fees for optional, virtual items that enhance . That strategy has proven lucrative for the newest generation of game companies, notably Zynga Inc., whose games are played mainly on Facebook.

"Wizard 101" has 25 million players and is launching in China this year. "Pirate 101" is currently being tested. It will be available to the general public later this year.