You're our last, best chance to keep history intact, so no pressure, buddy." That's Kronotek's Agent Dexter speaking to the player in Darkest of Days (http://www.vpltd.com/software/dod/), Virtual Programming's latest release for Mac OS X. Gamers step into the time-traveling shoes of Alexander Morris, who Agent Dexter plucks from the ranks of General Custer's army during the Battle of Little Big Horn. Now he must travel through history and relive some of its most famous events while protecting those whose survival is crucial to the space-time continuum.

Players' quest to keep the space-time continuum intact begins with the Civil War's Battle of Antietam and the Battle of Tannenberg during World War I. They soon learn that a mysterious organization called the Opposition is using its own time travel technology to stop them from protecting a Union Army corporal and a Russian Army officer. Darkest of Days' storyline later takes players to a World War II POW camp and Pompei on the day in 79 AD that Mount Vesuvius erupted.

Virtual Programming CEO Mark Hinton says that, by the end, players will learn the shocking secret behind the Opposition's motives, and they'll have had a chance to use futuristic weapons on long-ago battlefields. Enemies encountered in each of the game's five time periods fight the way combat was conducted then, heightening the immersive realism and allowing players to adopt different types of strategies for success.

Darkest of Days requires Mac OS X 10.6.5 or higher. It costs US$39.95.