So this is Emma. She's Olivia's daughter. And she was born with a purpose: to learn as much as she can about time travel (from Elliot and Katarina Jones, it turns out) - and then build and complete Titan, so that Olivia could carry out her plan to blow up time and create the Red Forest.
And this is Hannah. She's Katarina Jones's daughter. She's been fighting to keep time as it is, and her mother has recently sent her away, to live in 2007, and learn about the world: before the plague hits.
Katarina Jones, however, has been captured (by Deacon, who's on her side, though?) and is currently on Titan, taunting Olivia about the weapon that Primaries have built to destroy Titan. But Olivia has plans to steal the knowledge from inside Katarina's head.
Olivia hooks Katarina up to a machine with her and the two battle it out. Olivia tries to extract knowledge about the weapon with hallucinations about Cole, Cassie, and Hannah. But Jones proves to be tougher than that.
It's an odd look on Olivia, because she's relying on her OWN daughter, Emma, to complete her project, Titan. Emma starts to get completely demoralized by being forced to complete Titan. Olivia knows that without Titan, she has nothing, and she's starting to push Emma harder.
Katarina is forced to watch as Olivia murders a version of Hannah over and over again. It's torture. And Katarina finally succumbs and gives her a place and a date to find the weapon: England in 1491. It works! Katarina finally got Olivia to jump Titan to the place she needed.
Which means Dr. Adler and Team Splinter can track her through time and jump to 1491 themselves. It's a risk, they don't have enough processing power and they may never see home again. Still, the team decides to go forward with their plans. And head for the Middle Ages.
But right after Jennifer Goines jumps away, an intruder enters the Emerson Hotel/Splinter Lab. Cassie and Cole rush out to meet…old woman Jennifer Goines! Remember her? She lives in 2043 and knows more than we thought!
Jennifer tells them about her time in Medieval Times. The timelines are changing so much now that their noses are starting to bleed. Jennifer tells Dr. Adler to fix the splinter suit. And that she's in a lot of danger back in those times.
…it turns out that Katarina sent Hannah back in time to both live a life, and to find Marion Woods, the woman listed as Cole's mother on the birth certificate. She'll be wearing a blonde wig at a club in New York. When Hannah finally meets up with her…
Katarina confronts Olivia once more, and realizes she made one major mistake in getting her to the Middle Ages. She didn't mean to- but she gave up Deacon as a double agent. Olivia has sent him on a mission, but it's also a mission for his death.