The good news is that for a limited time, Blizzard has announced that they will be bundling a copy of Heart of the Swarm when you purchase the digital version of Legacy of the Void. Now this deal is ending and is only valid until the 25th of April, 11:59 PM PDT meaning that you have a little over 24 hours left to take advantage of it.
According to Blizzard, “If you don’t already own Heart of the Swarm or Legacy of the Void, your free copy of Heart of the Swarm will be added to your Battle.net account immediately when you purchase Legacy of the Void at the regular price. If you already own Heart of the Swarm, you will receive an email with a key for Heart of the Swarm (which you can give to a friend) within a few days of your purchase of Legacy of the Void.”
Legacy of the Void will be the last chapter in the current StarCraft 2 storyline. Blizzard is already starting to veer from the current story with the release of the Nova Covert Ops DLC, but the game is still worth checking out anyway. You can hit up Blizzard’s website if you’d like to place an order.