Fans will never forget the harrowing moment when Claire must leave Jamie in the past to keep Brianna safe. After living together for a few years, the protagonists of Outlander decided to separate, thinking it would be forever. Claire had to face, in 1948, that heartbreaking idea, knowing that Jamie had died 200 years earlier.
Claire's return to her own time represented a change for her and also for Frank, who accepted her again and faced the fact that the woman he loved no longer offered him her heart. Claire went through major changes with Jamie and the MacKenzie and Fraser clans, but back in 1948, she had to deal with her new reality.
The adaptation of the book
The producers of the series changed some aspects of the story told in the books. In this way, they hoped that fans would understand the timeline and all the events of Claire's return to 1948 (even viewers who had not read the novels).
With these details, the producers of the series invite the audience to use their imagination to understand what may have happened, before showing them reality. Thus, the production took viewers on a journey into the future and the past that was quite exciting and understandable.
Tobias Menzies and the construction of his character
Frank initially pressures Claire for answers, his personality didn't let the issue go unresolved. When she finally confesses the truth to him, he doesn't believe her, who would? The actor Tobias Menzies, confessed in an interview that he doesn't think his character completely believed Claire's story at the end.
It's clear that Frank is quite cerebral, so he is dedicated to putting together pieces, like the old dress, stories about the stones and research into the past. So, the construction of the character for that precise moment, was not based on conviction, it was based on the doubt of Frank.
The conversation that didn't happen in the books
The series changed some of the aspects of Claire and Frank's conversation about time travel. Claire told him everything about her life in the last two years: how she had to adapt to another time and how she fell in love with another man. With these confessions she made it clear to whom her heart belonged at that moment.
In the book Voyager, Claire tells Frank what happened through a flashback, but all too hastily, whereas in the series the female protagonist takes her time. The producers decided to expand on this conversation because it's an important aspect of the next 20 years. The reason why Frank agrees to raise another man's daughter marks the lives of all the characters, so they chose to give it more importance in the script.
The Claire of books and the Claire of the TV series
Time travel is not a simple matter. The person who travels through time can feel disoriented and distant from the reality in which they exist. For Claire it was shocking to go back, even though she knew what she was doing.
Time travel was difficult for her, because she had to leave Jamie and separate him from his unborn child. When Claire arrives at the hospital, she acts more delirious in the book, and laughs at the absurdity of the situation. On the TV show she is colder, serious and tries to push Frank away. The situation was assumed that way in the production to make it clear to Frank that Claire did not love him as she once did.
Claire's makeup
When Claire returns to 1948, she spends 20 years in this period, for that reason the physical change must be noticed. The make-up artists on the show wanted to make subtle changes to her, so they added some gray hair and wrinkles to her face.
Caitriona Balfe's performance was also important in demonstrating her age. The actress preferred not to the character in the makeup, but instead make changes in Claire that she felt were right for her age. To do this, she used a deeper in her voice and made a change in behavior and posture.
Sterile
Another difficult confession for Frank was about Claire's pregnancy. At first, he thinks the baby might be his, then he realizes it's been two years. So, Frank doesn't react well to the fact that the woman he loves is pregnant from another man.
Something that many fans didn't notice is that Frank realizes that he is likely to be sterile, which is why he didn't have children with Claire despite the years that they were together. This fact influences the decision to make. After thinking about it and assuming his position as an honorable man, he accepts reality. Frank is willing to be Brianna's stepfather, but he doesn't want her to know the truth about her real father.
The doctor in the books
It's 20 years before Claire and Jamie meet again. During this period, Claire goes through many experiences that make her more prepared to live in the 18th century. After her return to 1948, Claire began studying medicine and after her graduation practiced the profession.
Although the series shows this evolution, the books talk in more detail about the main character at this time. In the novel Voyager, Claire explains that she was a doctor before going to medical school (because of everything she learned in the 18th century). But these studies also offered her some additional knowledge, which she would later put into practice.
Claire can't change the past
When time travel is discussed, many viewers expect the protagonists to change the past. Claire tried, but, when she went back to 1948 and began to question about Culloden, she realized that her attempts did not change history, her friends lost the battle, again.
Although spectators can't clearly see it on the return to 1948, Claire actually begins to understand her role at that time. Later in time (during season four) Claire and Jamie it that none of their efforts to alter history were successful. For that reason, they try to make the best decisions, but knowing that, even if they have an advantage with history, they will never be favored by that knowledge.
The research of Frank and the Reverend
Another aspect of Claire's back in 1948 (but not known until later in history) is Frank's research. Although Frank forbade Claire to seek information about Jamie and Culloden, he and Reverend Wakefield continue the investigations to find more information about the time. Frank hides everything from Claire because he doesn't want his thoughts to return to Jamie, but he knows he's already lost her and begins to resent it.
Frank's anger and contempt for Jamie intensify over the years when he and the Reverend find an obituary of Jamie and Claire. In other words, Frank knows that Claire will be back any moment and begins to hate them for that reason. Claire only learns about Frank's investigation when Brianna discovers it and travels to the past to warn her mother of her imminent death.
Frank's lovers
When Claire returns to 1948 the relationship between her and Frank is not the same. Frank resents that she's in love with someone else, so he distances himself. Also, it should be noted that for him the situation is not fair. The book and the show have differences in this respect.
In the TV series Frank has a lover whom he wants to marry, while in the book he has different relationships with unidentified women. For this reason, it could be thought that Frank is less pleasant in the books in this regard.