Finally, a David-centric episode! It's been way too long since we've had one of those.
This episode gives us some long-wanted backstory on him, which is good, because he was seriously lacking in the backstory department. One of David's close friends is suspected of murdering two guys that die while mixed-martial-arts fighting with him, six months apart. This results in the angstiest David we've ever seen- in a good way. Kudo's to Alimi Ballard for his superior acting in this episode. But it all works out all right in the end, as usual.
Meanwhile, Charlie had to take Larry's seat in a poker tournament. And he was being overall awesome as ever. So basically, the moral of this story is that it's better to be an old friend of David than an old friend of Colby. (see "the mole")