DS9, season 7, ep 7, Once more unto the breach
I can never get enough of Klingon stories and Im grateful we got lots of good DS9 ones. Kor is growing old and senile, and asks Worf to help him die a warriors death. The idea of what honour means to such a complex character as Worf is always fun to explore, especially with such a good actor as Dorn.
TNG, season 6, ep 21, Frame of mind
Riker is imprisoned in alien insane asylum and told he has committed a murder, in an episode that would fit right in line with the darker tone of DS9. Frakes is amazing as a tortured Riker, in a episode unlike any previous episodes in TNG.
TNG Frame of mind
In a way this feels like a cheat, as it actually feels like it should be a DS9 episode. But it just shows the range of the writers and how flexible and confident they were becoming as the show started to come to an end.
Catch up with The Next Generation here in glorious HD
And the groundbreaking Deep Space Nine here