The X-Files: 5x14

The Red and the Black (2)

After the gathering at the abduction site where everyone is killed by the rebel bounty hunters, Cassandra Spender disappears and Mulder is blamed by her son, Jeffrey, who is an up-and-coming FBI agent. Meanwhile, the Syndicate is continuing their tests to create a vaccine for the Black Cancer and Marita Covarrubias becomes an unwilling test subject.