The episode "Once, Upon Time" begins with the Doctor, played by Jodie Whittaker, and her companions, Yaz and Dan, being scattered across time and space due to the Flux event. The Doctor finds herself in a surreal landscape, experiencing fragmented memories and timelines. She is confronted by the Weeping Angels, who are manipulating time and space, and she struggles to maintain her sense of self amidst the chaos.

Yaz and Dan, meanwhile, are thrown into different time periods. Yaz is in a war-torn setting, where she encounters a group of soldiers. She tries to help them understand the situation, but they are confused and frightened. Yaz feels a strong sense of responsibility to protect them, reflecting her internal conflict about her role as a companion and her desire to be a hero.

Dan, on the other hand, finds himself in a different time, facing a group of people who are also affected by the Flux. He is trying to make sense of his surroundings and is determined to find Yaz and the Doctor. His determination is fueled by his growing bond with Yaz and his desire to support her.

As the Doctor navigates her fragmented memories, she begins to piece together the nature of the Flux and its connection to the Time Lords. She realizes that the Flux is a manifestation of a greater threat, and she must find a way to reunite with Yaz and Dan to confront it. The emotional weight of her memories weighs heavily on her, as she grapples with the consequences of her past decisions.

The narrative shifts back to Yaz, who is now in a confrontation with the Weeping Angels. She uses her quick thinking and resourcefulness to evade them, but the tension escalates as she realizes the stakes are higher than she initially thought. The soldiers she is with are in danger, and she must act quickly to save them.

Dan's storyline intertwines with Yaz's as he encounters a familiar face from his past, which adds complexity to his character arc. He is forced to confront his own fears and insecurities, which are exacerbated by the chaotic environment around him. His determination to find Yaz becomes a driving force in his actions.

The Doctor, still fragmented, experiences visions of her past lives and encounters familiar faces, including previous incarnations of herself. These moments serve to deepen her understanding of her identity and the weight of her responsibilities as the Time Lord. She begins to formulate a plan to confront the Flux and the Weeping Angels.

As the episode progresses, the timelines of the Doctor, Yaz, and Dan begin to converge. The Doctor manages to locate Yaz and Dan, but they are still under threat from the Weeping Angels. The trio must work together to escape the clutches of the Angels, utilizing their unique skills and strengths.

In a climactic sequence, the Doctor devises a strategy to outsmart the Weeping Angels. They engage in a tense standoff, where the Doctor uses her knowledge of time to manipulate the situation. The companions support her, showcasing their growth and teamwork. The confrontation is fraught with danger, as the Weeping Angels are relentless in their pursuit.

Ultimately, the Doctor's plan succeeds, and they manage to escape the immediate threat of the Weeping Angels. However, the episode ends on a cliffhanger, with the looming presence of the Flux still a significant threat. The Doctor, Yaz, and Dan are left to ponder the implications of their experiences and the challenges that lie ahead, setting the stage for the next chapter in their journey.

At the end of "Once, Upon Time," the Doctor, Yaz, and Dan confront the Flux and the Ravagers. The Doctor realizes that the Flux is a time anomaly that is consuming everything. She manages to save her friends and herself by using the TARDIS to escape the Flux's destruction. However, they are left with unresolved questions about the Ravagers and the nature of time itself.

As the episode unfolds towards its conclusion, the Doctor, Yaz, and Dan find themselves in a fragmented timeline, experiencing moments from their pasts and futures. The Doctor is determined to understand the Flux and its implications, while Yaz grapples with her feelings of uncertainty and fear about their situation. Dan, trying to be the supportive friend, remains optimistic despite the chaos around them.

In a pivotal moment, the Doctor confronts the Ravagers, who are revealed to be manipulating time for their own gain. The Doctor's resolve strengthens as she fights to protect her friends and the timeline. She uses her knowledge of time travel to navigate through the chaos, piecing together the fragmented moments they experience.

As the episode reaches its climax, the Doctor successfully manages to stabilize the situation, but not without cost. The Ravagers are thwarted, but the Doctor realizes that the Flux is still a looming threat. The episode ends with the Doctor, Yaz, and Dan escaping the immediate danger, but they are left with a sense of foreboding about what lies ahead. The Doctor's determination to confront the challenges of time travel and protect her friends is evident, setting the stage for future conflicts.

In the final scenes, the Doctor reassures Yaz and Dan, emphasizing the importance of their bond and the adventures that await them. However, the lingering uncertainty about the Flux and the Ravagers leaves an ominous shadow over their journey, hinting at the challenges they will face in the episodes to come. Each character is left with a sense of purpose, but also a recognition of the dangers that time travel entails, reinforcing the theme of resilience in the face of uncertainty.

In "Doctor Who" Season 13, Episode 3 titled "Once, Upon Time," there is no post-credit scene. The episode concludes without any additional scenes or teasers after the credits roll. The focus remains on the narrative and character arcs presented throughout the episode, particularly the Doctor's struggle with the Flux and the revelations about her past and the Time Lord's history. The episode wraps up its story without extending into a post-credit moment.

In 'Once, Upon Time', the Doctor experiences a time loop that causes her to relive moments from her past and future. This loop is a manifestation of the Flux's chaotic nature, and it forces her to confront her own memories and choices. As she navigates through these fragmented timelines, she grapples with feelings of isolation and confusion, trying to piece together the events that are unfolding around her.

Yaz's character in 'Once, Upon Time' is marked by her growing sense of agency and determination. As she faces the challenges posed by the Flux, she becomes more assertive, taking on a leadership role among her companions. Her emotional state fluctuates between fear and resolve, particularly as she tries to support the Doctor while also dealing with her own insecurities about their relationship.

Vinder is introduced as a key character in 'Once, Upon Time', where he is depicted as a determined and resourceful individual. He is on a mission to find his lost love, and his journey intertwines with the Doctor's as they both confront the dangers of the Flux. Vinder's emotional depth is revealed through his longing and desperation, which drive him to make choices that impact the narrative significantly.

In 'Once, Upon Time', memory is a central theme as the Doctor and her companions navigate through fragmented timelines. The episode visually represents memories as tangible elements that can be manipulated and revisited. The Doctor's struggle with her own memories highlights her internal conflict and the weight of her past decisions, while also emphasizing the importance of memory in shaping identity and relationships.

The Weeping Angels make a chilling appearance in 'Once, Upon Time', serving as a metaphor for the fear of the unknown and the passage of time. Their presence adds a layer of tension and urgency to the narrative, as they embody the threat of being trapped in time. The Doctor's encounters with them force her to confront her own vulnerabilities and the consequences of her actions, making them a pivotal element in the unfolding story.

"Doctor Who" Season 13, Episode 3 titled "Once, Upon Time" contains several elements that may be considered potentially objectionable or upsetting for children or sensitive viewers. Here are some aspects to be aware of:

1. Violence and Threats: The episode features scenes with characters in peril, including moments of physical confrontation and implied danger, which may be intense for younger viewers.

2. Emotional Distress: Characters experience significant emotional turmoil, including themes of loss, fear, and existential dread, which could be unsettling for some.

3. Dark Themes: The narrative explores concepts of time, memory, and identity in a way that can be complex and potentially confusing, leading to feelings of anxiety or discomfort.

4. Mysterious and Eerie Atmosphere: The episode has a surreal quality with unsettling visuals and scenarios that may be frightening, particularly for younger audiences.

5. Death and Sacrifice: There are references to death and the consequences of actions that may be heavy for sensitive viewers.

These elements contribute to a tone that may not be suitable for all children, depending on their age and sensitivity to such themes.