We learn what is Thanatos in tonight’s penultimate episode before the mid-season finale. Plus we learn more of John’s time at Ultra, which is where we begin six years ago.

We see John be a willing participant in Jedikiah’s experiment that would make him a better agent i.e. the ability to kill. As the experiment goes on, it looks like John would follow in the other agents who attempted this meaning dead.

Jedikiah then wakes up in cold sweat in the present day and we see that he is with Morgan, his Tomorrow People girlfriend. He decides to go back home so as to not rouse suspicion.

Back at the Lair, Stephen keeps on insisting that he saw his dad and goes on and on about Thanatos and after doing some digging at Ultra realizes that Jedikiah probably knows the answers they seek.

A plan is formed where Cara and Russell will pay Jedikiah a visit at his place for the purpose of reading his mind. John and Stephen help them break in while in the Lair. At first it goes well, Cara sees Morgan in Jedikiah’s mind as well as a moment that he shared with John while he was an Ultra agent. From this, Cara later tells John that Jedikiah still cares for him like a son.

However, Russell can’t keep his hands off some of the nice things that Jedikiah has and makes a noise that awakens Jedikiah. Cara escapes but Russell can’t because his powers get taken away by a device that Jedikiah turns on. The fight for a bit but Russell manages to turn off the machine and teleports away but Jedikiah tags along.

No one is happy that Russell had accidentally kidnapped Jedikiah but Cara sees this has an opportunity to find out more about Thanatos. John warns Cara to be careful to no reveal that she still has her powers as this will also compromise Stephen.

While being interrogated by Cara, Jedikiah manages to close his minds to her telepathy and she gets no where with him and when he taunts her with her past, she beats him up pretty well till John stops her.

Meanwhile, Stephen has been summoned by Ultra because of his uncle’s kidnapping. A braintrust, a trio of telepaths are linked together to try and find Jedikiah. At the same time, Stephen meets the Founder in the flesh after only meeting his voice in a previous episode.

To throw Ultra off their scent from locating the Lair, they put them on the trail of Jedikiah’s girlfriend Morgan. Ultra pays her apartment a visit but she escapes but Stephen captures her and wants to know the nature of her relationship with his uncle. She says she loves him and thought he loved her too and can’t believe he would seek Ultra on her. Stephen lets her go and says his uncle wasn’t behind this ambush.

But Cara threatens to expose Jedikiah’s relationship with Morgan to Ultra to get Jedikiah to talk. This gets him talking. He explains that Thanatos is a man called Aldous Crick. We get an address where Crick is and Stephen, John and Irene (who tags along because she probably can understand science stuff that Crick will say).

At this meeting with Crick, we learn that he is one of the founders of Ultra, which was originally formed to protect the Tomorrow People but Jedikiah’s jealousy of his brother led him to corrupt Ultra for nefarious purposes. Science stuff was talked about like the ability to stop time was something Stephen’s father could. There is talk about teleporting while stopping time makes you in some sort of limbo.

At Ultra, the Founder plugs himself in the Brain Trust and manages to almost locate the Lair but John takes up topside to an Ultra safe house that we saw earlier in a flashback. In the flashback, this is where Jedikiah took John to his first mission. He is tasked to kill a man. When he does, he learns it was a test. His real mission is to kill the man that trained him. John doesn’t understand why but Jedikiah insists that this must be done.

We learn that this man is Roger, Stephen father. We see the car explosion that Jedikiah showed Stephen in another episode. But Roger teleported away. John wants to know why he betrayed Ultra and responds that he did it to protect their people. John shoots Roger but is immediately remorseful. He leans over Roger’s body and as he lays dying, he gets John to vow to protect the Tomorrow People and to find his son. John promises him just as Roger dies.

Back to present at this safe house, Ultra has found Jedikiah and John. John can’ teleport away and he tries to fight off the Ultra agents but he is beaten into defeat and is brought into Ultra. John sees Stephen knowing the truth that he killed his father.

So next week, is the mid-season finale and see Stephen insisting that his father didn’t die but is in this limbo that we learned in this episode.