“Let He Who Is Without Sin…” is episode seven of season five of Star Trek: Deep Space Nine.
Dax has managed to talk Worf into going to Risa with her (since “Looking for par’Mach in All the Wrong Places” they have been an item). Given that this is a vacation planet, Worf is not exactly looking forward to it, as he isn’t a big one for fun – which, as Dax points out, makes him different to most Klingons. Worf is also struggling with what he considers to be Dax’s frivolity when it comes to their relationship.
Dr. Bashir and Leeta, the dabu girl, also accompany them, although they promise they won’t get in the way. Quark also comes with them, because that was the only way that he would give Leeta the time off. This makes Worf unhappy to start with.
When they arrive on the planet, the rest have fun but Worf remains in his Starfleet uniform, getting more and more annoyed. Also on the planet are a group calling themselves the New Essentialist Movement. The Essentialists believe that the Federation has turned away from its original values, and by doing so made themselves weak and vulnerable to the Klingon Empire, the Romulan Empire, the Dominion and the Borg, as well as anyone else who wants a piece of them.
Worf finds much to approve of in the Essentialist’s cause, so he joins with them in trying to show those on Risa just how vulnerable they are. At least, until the Essentialist leader goes too far. Worf also reveals some details of his childhood amongst humans, and why he is more restrained than other Klingons.