Your grandchildren come to visit you and ask you to tell them a story. You tell them about the time you spend as commander in a past war. But all you can remember are those difficult returns from the taverns. You know, those times were you struggled to get yourself and your soldiers back from the tavern to reach the camp before the general noticed your absence and assign you latrines clean up duty as punishment. So you try to build an epic war story for your grandchildren while reliving your tavern return memories.
It's not epic, but it's definitely interesting. This being said, I don't think you need it: this is just contextual, and the current "introduction" part already explains the goal of the game very well.
Thanks Zorga. You're right! This would be redundant information. Anyways, people can read the story in this blog if they really prefer reading over playing the game.