Never have I seen a story trailer for a videogame sum up the entire plot so completely that the second half of the video is spent rehashing the plot.
DeathSpank is about a hero, named DeathSpank, who is on a quest to obtain the ultimate artifact (known only as the artifact). DeathSpank is attempting to achieve his goal of being worthy to wield the mighty artifact by being a friend to the downtrodden and a dispenser of justice. Yep, that's about it. You can still watch the video is you want; there's some gameplay footage mixed in that's pretty cool.