Symbiosis, TNG 1
Here’s a classic Trek-as-allegory episode, and surprisingly well told, too. In the first act we meet some very spaced-out, dare I say stoned aliens. Then we learn they are dying and need their “medicine” that only the other aliens can give them. Turns out this is an “Opium Wars”-type scenario, with Planet A purposely keeping Planet B addicted for their own (and only) financial gain. How can Picard put a stop to this without violating the Prime Directive? (Oh, Prime Directive Shmime Directive — Kirk never had this problem!!!)