Jessica Logan is the wife of Wyatt Logan.
Jessica was mysteriously murdered in San Diego, California. One night, Jessica and Wyatt were out at a bar when she ran into an ex-boyfriend. Wyatt became jealous and drunk, and the two were arguing while driving home. Jessica yelled at Wyatt to pull over, and got out of the car. Wyatt later came back for her, but she was gone. The police later found her body after she had been strangled. (“The Watergate Tape”) Wyatt blamed himself for her death. (“Pilot”)
When Wyatt helped Garcia Flynn capture Benedict Arnold, he promised that he'd give Wyatt the name of Jessica's killer. (“The Capture of Benedict Arnold”) Wyatt then cooperated with Flynn to capture Arnold. Flynn revealed the name of Jessica's killer to be Wes Gilliam, a man serving for the murders of two other women at San Quentin State Prison. (“The World's Columbian Exposition”)
Later, Rufus Carlin and Wyatt steal the Lifeboat to prevent the conception of Wes and therefore prevent the murder of Jessica. Despite Wyatt being successful in preventing the conception of Wes, Jessica continued to remain dead. This implies that Wes was not the true murderer of Jessica. (“Karma Chameleon”)
Rufus later discovers that Rittenhouse went back to 1980 San Diego, somehow reviving Jessica. She's less happy to see Wyatt, as Wyatt's been ignoring her texts and walked out of their marriage counselling session. Jessica asks Wyatt for a divorce, claiming he was constantly drunk and unable to change for long. In order to excuse his previous self's actions, Wyatt proves to Jessica time travel's existence, much to the dismay of Agent Denise Christopher. (“The Salem Witch Hunt”) She then begins to stay in the bunker with Wyatt along with the rest of the crew, spending large amounts of time with Wyatt and everyone else. (“The Kennedy Curse”)
When Wyatt helps an injured Lucy Preston, Jessica realizes that Wyatt is in love with Lucy, and decides to walk away. Lucy, though, stops Jessica and convinces her to stay by telling her about Wyatt's attempts to save her life. Wyatt later tells Lucy that Jessica has agreed to give him a second chance because of what she told her. (“The Kennedy Curse”)
Agent Christopher and Connor Mason later find pictures of Jessica on some damaged Rittenhouse servers, suggesting she may be more involved with Rittenhouse than they had known previously. (“Mrs. Sherlock Holmes”)
Wyatt later sees Jessica looking at pictures of her family, and sees that there are pictures of her brother, Kevin. However, Wyatt tells Jessica that in his timeline, Kevin died of leukemia as a boy. Jessica tells Wyatt that she vaguely remembers him being treated by a cutting-edge stem cell treatment, making Wyatt suspicious of how her parents were able to afford that. However, Wyatt is distracted when Jessica reveals she is pregnant. (“The Day Reagan Was Shot”)
Mason and Agent Christopher show the pictures of Jessica to Wyatt, Lucy, and Rufus, and ask Wyatt if there was anything off about Jessica that supported the idea of her being involved with Rittenhouse. However, Wyatt refused to believe she was a part of it. He threatens to leave when Agent Christopher says Jessica has to move out of the bunker. Jessica later reveals that Agent Christopher suggested the idea, and Wyatt supports this, telling Jessica she should leave so she can keep up with doctor appointments for the baby. The next morning, though, Jessica kidnaps Jiya and steals the Lifeboat, revealing herself to be a Rittenhouse agent. (“The General”)
After delivering Jiya and the Lifeboat to Nicholas Keynes and Carolyn Preston, it becomes clear that her mission was to infiltrate the bunker and then to kill everyone. However, Jessica couldn't bring herself to murder her husband, so she opted to steal their time machine and one of their pilots instead. Jiya, though, manages to escape, and ends up stranded in 1888. (“Chinatown”)
Jessica travels back with Nicholas, Carol, and Emma Whitmore in order to get the Lifeboat back. There, Wyatt confronts Jessica, who explains that Carol and Emma saved Kevin's life, and then proceeded to indoctrinate her into Rittenhouse. They raised her from childhood and became her "family". When asked by Wyatt if she is actually pregnant, she says she is, and that he is the father. Despite his pleas, she refuses to leave Rittenhouse, as she must protect her "family" and her baby. During a subsequent shootout in a saloon, Flynn wounds Jessica in the arm, but she manages to escape with Emma. (“Chinatown”)
Jessica subsequently becomes Emma's lieutenant and is sent back to 1848 to get a lot of gold from the last remaining Rittenhouse sleeper agent. At the same time, a battle-hardened future Wyatt reveals that Jessica was never pregnant and it was another manipulation. While going through the future Lucy's journal, Wyatt realizes that Jessica is the reason for everything that has happened and that to save Rufus, she has to be removed from the timeline. At night, Flynn slips away from the rest of the team and uses the Lifeboat to go back to February 11, 2012, the night that Jessica died in the original timeline. After walking away from Wyatt, Jessica calls the Rittenhouse agent sent to protect her only to find him dead and Flynn standing nearby, suffering from the debilitating effects of traveling back in his own timeline. Jessica and Flynn fight with Jessica having the upper hand at first, but Flynn eventually manages to recover his gun and shoot her dead.
Jessica's death removes her actions from her history, restoring Rufus at the cost of Flynn's life from traveling back into his own past. Additionally, as a result of Jessica being gone, Lucy and Wyatt never broke up. Wyatt realizes that Flynn had lied to him about the name of Jessica's killer and now understands that all along, Flynn had been trying to save his life instead of ruin it.