The heir to the throne is shared by four brave people: Darius, Simon, Thales, and Sonia. The 19 gods of Olympus left behind an omnipotent stone to the great emperor Achilles, who has ordered a search to be conducted for the stone. You take the role of one of these four in an effort to find the stone on the island before the rest, waging war with opponent armies to prevent them from finding it first.

19 is somewhat unique among turn based strategy games, in that turns are taken in real time, following rules that are reminiscent of the Japanese chess-like game known as Shogi. The game takes place on an overworld map, on which players take turns moving troops. When opposing troops vi for the same location, the game switches to a zoomed-in combat screen, showing each individual member of the opposing forces. While the story of the game revolves around finding a stone, there is no actual stone to discover. Your only goal is to wipe out the armies of the other three opponents.