Nemesis

Chakotay's shuttle comes down on a jungle planet, where he is found by the Vori, soldiers waging a desperate war against the Kradin. At first an outsider, he is gradually drawn into their struggle. He shares their hardships, picks up their distinctive way of speaking, and watches in horror as Kradin troops appear to commit atrocities against villagers and his new comrades. Meanwhile Janeway works with the Kradin ambassador, Treen, to find her missing first officer. By the time Tuvok reaches him, Chakotay is so consumed by hatred that he sees his rescuer as one of the enemy. The truth emerges: the whole ordeal was a Vori indoctrination programme, using drugs and staged experiences to turn recruits against the Kradin. Back on Voyager, Janeway admits she cannot say which side is in the right, and Chakotay finds that the hatred planted in him does not simply disappear.