The Tomorrow People (US) - Season 1 Episode 21 -

When the Tomorrow People learn the truth about the serum they were injected with, Stephen and Cara attempt to buy time for Jedikiah while he tries to create a possible antidote. Growing impatient, Russell and the other rogue Tomorrow People make a rash decision to sacrifice Roger to Ultra for their own safety. Meanwhile, John is having a hard time figuring out his new role and the only one he can turn to for advice is Astrid.