London 2017

Two kids are going into the mausoleum. A voiceover talks of a serpent...two heads always forward never back.

They call Jennifer a bloody bag lady. She owns the mausoleum. She's just waiting around for the dying man. 

The lights begin to flicker...here's Johnny!!

1891

Cassie and Cole are meeting Athan. He's in full on pity mode, which is not good for a guy who could be responsible for the end of the world as we know it. They synchronize their vests and begin running through several different timelines, with Jones and friends tracking them.

Athan sets Cassie's destruct button to throw them off. They get rid of Cassie's vest and go after Athan. Cole destroys Athan's vest and the three tandem to their home. 

The conversation between parents and son doesn't go so swimmingly. Athan tries to get Cole to pull the trigger, but Cole won't do it despite the taunts. 

Olivia is making red leaf tea to find where they are. Deacon wants to know when Jones is going to reach her tolerance for batshit. Sending her consciousness up the timestream?

But Olivia gets her answers. As soon as she does, Athan feels it. 

While Cassie and Athan show each other their matching Eliza watches, the place is riddled with bullet holes. They're here.

Big shootout. Inside, Jones gets Athan in her sites. She apologizes to Hannah and shoots Athan's vest. Hannah looks at Jones and wonders, "what have we done?"

Outside there are people from Titan. The "nice" dude who was there for Cassie while she was being held hostage. They are taken into the ceremony room. Olivia kills the Pallid Man. 

Olivia made it out. How? Deacon finally put everything together. It was just a long con. She killed people, escaped and took the place of the Witness.

Jennifer saves the dying man. The Witness takes his rightful place at the ceremony and everyone runs. Bullets are flying flying flying.

Cole, Cassie and Jones escape. 

Athan tells Olivia she's the Witness. She always has been. She's shocked.

In 2018, Athan says goodbye to Jennifer. It's up to her now. 

Meanwhile, James is listening to his father tell him a story. James looks exactly like Athan did as a child. It's the story of the serpent. And who wrote it? His mother.