“Kill or be Killed” is episode four of season one of The Tomorrow People.
The episode starts off 15 years before the present, when a young John is a foster child and Jedikiah comes and finds him. There are flashbacks during the episode of John’s time with Ultra.
Killian McCrane, a former Ultra agent who, unlike the rest of the Tomorrow People, is able to kill after Jedikiah managed to weaponise him, although with unfortunate side effects, has resurfaced. Stephen wants to go after Killian, but John is less interested, until Killian shows that he wants John.
Jed wants John’s help to stop McCrane, and John agrees.
It turns out John can kill too. How many of the Tomorrow People will be able to kill by the end of the series? They don’t seem to be keeping with the spirit of the original.