Rittenhouse bombs Mason Industries, with Wyatt, Rufus, Jiya, Mason, and Christopher as the only survivors. Christopher moves them all, including the damaged Lifeboat, to an abandoned military bunker.
Six weeks later, Lucy has integrated herself into Rittenhouse and joins her mother Carol and Emma on a trip to a World War I battlefield in order to save a wounded soldier. Lucy and Carol get the help of Marie Curie and her daughter Irene in order to use an early X-ray machine, so that Emma can extract the shrapnel from the soldier. Wyatt and Rufus are forced to fight and kill a Rittenhouse sleeper agent, and they're shocked to find a smartphone on his person with a manifesto. When Lucy's betrayal is revealed, Emma threatens to kill her despite Carol's orders, but Wyatt forces an exchange of Lucy for the wounded soldier, Nicholas Keynes.
Back in the present, Wyatt theorizes that Rittenhouse has placed sleeper cells throughout history in order to shape it as they see fit. Lucy learns that Emma, under Carol's orders, has ensured that her sister can never be brought back. It turns out that Keynes is Carol's grandfather and Lucy's great-grandfather. Christopher goes to talk to the imprisoned Flynn, who claims he'll only speak with Lucy.
- Almost Kiss: Lucy and Wyatt almost kiss after her return. Jiya walks in at just the wrong moment.
- Angst: Losing everything hits Mason hard. Most of his employees are dead, and he's forced to either sit around in a secret bunker or take his chances with Rittenhouse out to kill him for betrayal. He keeps rewatching the video of his building blowing up. He feels useless, having not been a real engineer in a long time. He gets better by the end of the episode and develops the means to track where the Mothership has been.
- Back from the Brink: Despite the multiple arrests in the Season 1 finale, Rittenhouse is still in existence and is working to undo the damage the protagonists have done to it.
- Contrived Coincidence: Carol takes Lucy on their first mission on the Mothership roughly at the same time as Rufus and Jiya finally fix the Lifeboat.
- Deep Cover Agent: Rittenhouse have placed sleeper cells throughout history in order to reshape it the way they see fit. These agents will work their way up the ranks in order to reach key positions.
- Evil All Along: Emma is revealed to have been a Deep Cover Agent for Rittenhouse all along, working with Flynn only when it suited Rittenhouse goals. She resents Lucy for her privileged position, claiming that, not being "royalty", she had to work her butt off to get to where she is. She (rightly) distrusts Lucy's FaceHeel Turn.
- Fake Defector: Lucy claims to have integrated into Rittenhouse. In fact, she plans to destroy the Mothership in order to stop Rittenhouse from messing with history. Emma correctly suspects her, while Carol does her best to bring her daughter over to their side.
- Grandfather Paradox: Almost (possibly) happens when Lucy tries to kill Keynes, not knowing that he's her great-grandfather. It's not clear if she and Carol would be affected, as they are in the past at the time. Also, the next episode reveals that Keynes already has a daughter, so his death wouldn't have made a difference (in fact, he probably did die in the original timeline, given that Carol felt the need to save him).
- If You're So Evil, Eat This Kitten: When Keynes's fellow soldier witnesses a defibrillator at work, Emma wounds him and then forces Lucy to kill him. Lucy does it to prove her loyalty to Rittenhouse. Later, she reveals to Wyatt how conflicted she feels about it.
- Oblivious to Love: It's obvious to everyone that Wyatt has feelings for Lucy, but he himself refuses to admit it. This was hinted at during the Season 1 finale, when he is finally able to accept his wife's death and move on.
- Ret Gone: Apparently, Emma has done something in the past to ensure that, no matter what Lucy tries, she can't bring Amy back. Presumably, Carol had her do this in order to avoid her own coma.
- Suicide Mission: Thinking that Rufus and Wyatt were dead, Lucy was planning on killing the wounded soldier and blowing up the Mothership with her inside, thus preventing Rittenhouse from having a time machine.
- Time Skip: Six weeks pass between the end of Season 1 and the proper beginning of the episode.
- Visionary Villain: Apparently, Nicholas Keynes predicted the possibility of time travel in 1910 and has written down a manifesto in which he advises Rittenhouse how to use the technology to reshape history. Carol, his granddaughter, brings him with her to 2018 in order to enact his plan.
- Wham Line: Carol telling Nicholas Keynes that she's his granddaughter.
- Wham Shot: At the beginning, in 1918 France, an American army captain retrieves his pouch from under a dead soldier and pulls out a smartphone, revealing that not only is he from the present, but he's been in the past long enough to rise up through the ranks.
- World War I: Lucy, Carol, and Emma travel to a battlefield in 1918 France in order to save a wounded soldier and bring him back to 2018. The episode's title refers to what many believed about the Great War at the time.