Maiya begins to experience dimensional phasing. Augur explains that this is likely a result of her sharing a reality with her doppelganger Isabel Martinez, and it can only be resolved by the two merging into one, which will likely result in one of them being erased from existence. Sandoval orders Lili to bring "Isabel" up to the mothership for questioning, and Lili is forced to arrest Maiya, while Liam goes to Canada to try to locate the real Isabel. He finds her in a First Nations village and convinces her to undergo the merge with Maiya.
Meanwhile, Jonathan Doors announces that he's running for president and is shutting down the Resistance, deciding to take their fight to the public. He sells the now-empty headquarters to Augur. Zo'or invites Doors up to the mothership for a conversation. Liam and Lili hatch a plan to sneak Isabel up as part of Doors's security team. Lili shows Isabel a photo of her father and learns that they are indeed half-sisters.
Sandoval questions Maiya, beginning to experience Jason's memories, eventually realizing who she is and where she's from. Zo'or meets with Doors and offers him the public endorsement of the Taelons in exchange for Doors agreeing to accelerate the human enhancement project once he's president. Doors refuses. Liam stages a shuttle malfunction, distracting Sandoval and the guards. Maiya meets Isabel and tells her to fight to survive when they merge, but Isabel refuses to fight, claiming that they are one, so as long as one of them survives, then the other won't be truly dead. They come together, and Maiya ends up as the survivor. Liam has her switches clothes with Isabel, leaving the dead body for Sandoval to find. Sandoval questions Liam and is angry that he withheld the truth about his trip to the other world from him. He threatens to punish him, only for Liam to explain that he told Da'an everything, and that Da'an supported his actions. Lili talks to Maiya, who reveals that she now carries a part of Isabel within her and offers to tell Lili more about her father.
- Character Title: The episode is named after Isabel Martinez.
- End of an Age: With Doors choosing to accept the presidential nomination and go public, he shuts down La Résistance. He sells the DC headquarters to Augur with the provision that he may still have access to it in case of emergencies.
- Flash Sideways: Sandoval begins to see memories that are not his own. They actually belong to his dead doppelganger Jason from Maiya's world. Augur believes it's because of his CVI coupled with the dimensional phasing weakening the barrier between the two worlds. The experience becomes even stronger when he touches Maiya's hand during one of her phasing episodes.
- Internal Reveal: Sandoval learns of Liam ending up in another world.
- Never the Selves Shall Meet: Maiya and Isabel sharing a universe causes them to begin experience dimensional phasing, with episodes getting more frequent and painful. When they finally merge, Maiya survives. Isabel dies, but a part of her, including her memories and thoughts, stays with Maiya.
- Nice Job Fixing It, Villain: Zo'or offers Doors the Synod's full endorsement in exchange for his cooperation once he's president. Not only does Doors reject his offer, but he makes the details of the meeting public at his next interview, boosting his own popularity and showing everyone that President Thompson is a Taelon puppet. Zo'or vows to never underestimate another human again.
- The Reveal: Isabel is indeed Lili's half-sister, just as Maiya suggested. Strangely enough, though, Maiya and Kayla were implied to be full sisters or at least had the same mother, while Lili and Isabel only share a father.
- Secret Other Family: Lili's late father, Colonel Edward Purcell, met Isabel's mother around the same time he was divorcing Lili's mother. They got married and had a daughter. According to Isabel, it seems his unfortunate experience with Lili and Andy has resulted in him being a better husband and father this time around. She doesn't learn much over this conversation, but at the end of the episode Maiya offers to tell her more, now having access to Isabel's memories.
