Blizzard Entertainment says StarCraft II: Heart of the Swarm, the first expansion to the company's real-time strategy game StarCraft II: Wings of Liberty, will be available in stores and online beginning March 12, 2013.

Here's how the expansion pack is described: "Heart of the Swarm features a new campaign continuing the epic story of Sarah Kerrigan, Queen of Blades, as she gathers the remnants of the zerg Swarm and plots her revenge against the treacherous dictator of the Koprulu sector, Arcturus Mengsk. It also introduces several new multiplayer units and features that enhance the acclaimed StarCraft II online experience."

StarCraft II: Heart of the Swarm will be available on DVD-ROM for Mac OS X and Windows at a suggested retail price of US$39.99. The expansion will also be available digitally directly from Blizzard’s StarCraft II website (www.StarCraft2.com) at an expected price of $39.99.

Blizzard is offering a Collector's Edition of Heart of the Swarm loaded with digital and physical bonus items, available exclusively at select retail stores for a suggested retail price of $79.99. Players will also have the option of purchasing a Digital Deluxe version of the expansion, which will include all of the digital items from the Collector's Edition.

The Digital Deluxe version will be available directly from Blizzard via www.StarCraft2.com at an expected price of $59.99. Players who purchase the standard edition digitally or at retail will have the option to upgrade to the Digital Deluxe version at any time (for as long as the standalone Digital Deluxe version remains available) for an additional $20.