Jennifer Walters, Tatiana Maslany, begins her journey as a talented lawyer preparing to deliver closing arguments in a high-profile case. Her paralegal, Nikki Ramos, Ginger Gonzaga, encourages her, warning that she might need to "Hulk out" if the pressure becomes too much. With a confident smile, Jennifer breaks the fourth wall to share her secret with the audience: she is a Hulk. The story flashes back to events leading up to her current situation, revealing that she was riding in a car with her cousin, Bruce Banner, [Mark Ruffalo], who has managed to stabilize his Hulk form thanks to an inhibitor device. Despite some lingering injuries from the Snap, Bruce’s recovery allows him to stay in human form, which is healing his broken arm from the events of Endgame.
During their trip, Bruce mentions their relative Ched, sparking Jennifer’s curiosity about American hero Steve Rogers, aka Captain America. She humorously deduces that Steve was a virgin, prompting Bruce to laugh. Suddenly, their vehicle is interrupted by a spaceship appearing abruptly in front of them. Jennifer swerves to avoid it, causing their car to tumble down a hill, and during the chaos, the inhibitor device breaks. As Bruce begins his transformation, he notices blood trickling from his wound and urges Jennifer to stay back, but inevitably, some of his blood drips onto an open wound on her arm. Almost instantly, Jennifer transforms into her powerful Hulk form and disappears into the unknown.
When she awakens, Jennifer finds herself in a remote area. She stumbles into a bar to use the bathroom, where a group of women, mistaking her disheveled appearance for evidence of an abusive relationship, take pity on her. Outside, she encounters several men who are insistent and unwilling to accept her refusal. In her Hulk form, she quickly dispatches them. Later, she wakes up in a bed, wearing clothes that fit her, and explores her surroundings, discovering she is in Bruce’s underground laboratory, sponsored by Tony Stark. Bruce has already contacted her family, ensuring they know she is safe.
Bruce explains that the gamma radiation from his blood entered her system, giving her unique abilities. Thanks to their shared genetics, Jennifer can synthesize gamma radiation into a different form. He confirms that her blood not only gave her powers but also healed his broken arm entirely. To prevent any further issues, he destroys her blood samples, fearing they could trigger another Hulk transformation. Jennifer, eager to regain her normal life, asks Bruce if there’s a way to control her Hulk state. Bruce admits that her Hulk identity is now integrated into her life, and he proposes a training plan that spans about 15 years, focusing mainly on controlling when she transforms.
Bruce devises a series of exercises to help Jennifer harness her powers, including steel-walled rooms, Tai Chi sessions, and physical feats like throwing rocks and balancing. They humorously bond over her newfound strength and an alcohol binge that she can enjoy without getting drunk. During this training, she expresses her frustrations about everyday stresses—like harassment and mansplaining—as a working woman. This leads to her first unintentional transformation into She-Hulk, followed by her rapid return to Jen. Recognizing her agency, Jennifer decides to accept her Hulk form and dismisses the idea of becoming a traditional superhero, opting instead to enjoy life on a beach away from the chaos.
Her decision sparks an intense Hulk fight with Bruce, resulting in the destruction of his bar, which they work together to repair. During this, Bruce, reluctantly, promises to support her decision to pursue a legal career and return to her law firm. Jennifer then resumes her role at her law firm, where she confidently presents her closing arguments in court. Just before she finishes, a superpowered woman breaks into the courtroom, prompting Nikki to encourage Jennifer to turn into She-Hulk and handle the threat. She transforms seamlessly, dispatching the attacker with ease, then reverts back to her human form, eager to continue her legal work.
In a humorous mid-credits scene, Jennifer discusses Steve Rogers, revealing her desire to experience normalcy and her disapproval of his lost opportunities, before the credits roll.
In the next episode, Superhuman Law, Jennifer faces the fallout from her public heroics. She visits a bar with Nikki, where Jen, in her She-Hulk form, receives applause. But her day takes a turn when another attorney criticizes her for hiding her powers and she is subsequently fired from her position due to concerns about bias, which she drunkenly laments. Struggling emotionally, she visits her family, where her relatives reveal little support, but her father encourages her to move forward.
Through chance, she meets Holliway, who offers her a job at GLK&H with the stipulation that she always be She-Hulk at work. Jen is hesitant but agrees, transforming as she enters her new role in the "Superhuman Law" division. Her first case involves parole for Emil Blonsky, the Abomination, whom she initially refuses to see due to his past attempt on Bruce’s life. However, Holliway insists, and Jen enters the prison to meet him—where she is required to sign disclaimers and see him in his human form. Blonsky expresses remorse, reflecting on his desires to become a hero and achieve peace, while also revealing his efforts to transform and live peacefully.
Later, Blonsky’s parole is discussed, and Jen witnesses his transformation into Abomination during the hearing. Despite her protests, he maintains his personality in his monstrous form, supported by his seven soulmates, who testify on his behalf. Wong, Benedict Wong, unexpectedly arrives, providing testimony on Blonsky's rehabilitation and the lawful return to his prison cell. The judges consider his case, noting his desire for peace and his efforts to live a quiet life.
Meanwhile, a controversy erupts over the legality of Blonsky’s transformations, and Jen’s efforts in court are challenged, but she manages to present compelling evidence of her own identity as She-Hulk, which helps her case. The series humorously explores her legal battles, personal frustrations, and the challenges of balancing her superhero identity with her career and personal life.
As her reputation grows, she becomes more confident, embracing her Hulk identity publicly while navigating the complexities of her legal profession. She is also seen dealing with trademark issues from Titania, who has registered the “She-Hulk” name for her own products, prompting Jen to file a countersuit. She explores fashion options with Luke Jacobson, Luke, to craft outfits suitable for both Jen and She-Hulk, symbolizing her journey toward self-acceptance and empowerment.
In subsequent court cases, Jen’s assertions about her early use of the She-Hulk persona and her dating history help solidify her identity, leading to a legal victory that orders Titania to cease her misuse of the name and cease selling her products under it. After the court, Jen celebrates her success with Nikki, reflecting on her evolving role as both a lawyer and a superhero. Her adventure continues as she dons her new outfit, with a hint at a surprise cameo involving her classic superhero alter ego, Daredevil, in the form of a yellow helmet set aside in her wardrobe, indicating exciting future possibilities.
