The episode explores the theme of trust as Mia's secretive behavior leads to suspicion among her peers. Characters like Niklas and other classmates begin to question Mia's intentions, which creates a rift in their relationships and highlights the fragility of trust in their competitive environment.

In this episode, Mia conducts an experiment involving a new biohacking technique that she believes could enhance human capabilities. She is particularly focused on the effects of a specific serum on the human body, which she hopes will yield significant results.

Mia's relationship with her classmates becomes increasingly strained in this episode as her secretive nature and the intensity of her experiments create tension. Her classmates begin to suspect that she is hiding something, leading to feelings of distrust and isolation.

Jasper plays a crucial role in Mia's experiment by providing her with access to necessary resources and equipment. He is both intrigued and concerned about the ethical implications of her work, which adds complexity to their relationship.

Mia faces a significant internal conflict regarding her biohacking practices, as she grapples with the moral implications of her experiments. She is driven by a desire to achieve groundbreaking results but is also haunted by the potential consequences of her actions on herself and others.

"Biohackers" Season 1, Episode 4 titled "Certainty" contains several elements that may be considered objectionable or upsetting for children or sensitive viewers.

1. Medical Experiments: The episode features scenes involving medical experimentation and biohacking, which may be unsettling for some viewers due to the ethical implications and the portrayal of scientific manipulation.

2. Tension and Conflict: There are moments of intense emotional conflict and tension between characters, which may evoke feelings of anxiety or discomfort.

3. Themes of Betrayal: The episode explores themes of trust and betrayal among friends, which can be emotionally charged and may resonate negatively with younger audiences.

4. Violence and Threats: There are instances of implied violence and threats that could be distressing, particularly for sensitive viewers.

5. Mature Language: The dialogue includes some mature language that may not be suitable for younger audiences.

These elements contribute to a narrative that is more suited for older teens and adults rather than a family-friendly viewing experience.