Last of Them

Set post S1. It's an unwritten rule of the Musketeers not to delve too deeply into another man's past; it's simply enough to be one of the brotherhood. But when their Captain goes missing, the Musketeers realize the only way to save him is to learn what he's kept hidden for so long. And these men would willingly go through Hell to rescue the man who at one time saved them all.