Ursula Henderson, the 21-year-old daughter of Dustin Henderson and Susie Bingham, arrives in Hawkins, Indiana, in 1986 from a dystopian 2024 with a singular mission: to prevent the deaths of Eddie Munson and Max Mayfield while stopping Vecna and his reign of terror. Armed with extensive training and powers linked to Hawkins Lab's legacy, Ursula must navigate a chaotic and unpredictable timeline while keeping the Party alive.

Her arrival does not go as planned. Ursula lands too late to save Chrissy Cunningham, and Eddie Munson is already on the run for her murder. Struggling to earn the trust of the Party, Ursula relies on her knowledge of key events and letters from their future selves to convince the Party of her legitimacy.

As Ursula integrates into the Party, she forms a close bond with Eddie, whose humor and resilience begin to break through her guarded demeanor. Max Mayfield becomes a central focus of Ursula's mission as Vecna targets her through her past trauma. Ursula steps into a leadership role, helping the group fight off Vecna's mental assaults using music and her growing understanding of her abilities. However, each victory comes at a cost, as Ursula's interference creates ripples in the timeline that she cannot fully predict or control. Her powers, particularly her shielding ability, manifest during deadly encounters, proving both a valuable asset and a source of mystery for the group.

Vecna, recognizing Ursula as a unique threat, becomes increasingly obsessed with her. His attempts to manipulate her psyche are met with fierce resistance, but Ursula's trauma and guilt over her mission begin to weigh heavily on her. Despite this, she pushes forward, leading the Party into increasingly dangerous territory in their quest to stop Vecna. The strain of leadership, her growing attachment to Eddie, and the toll of her powers push Ursula to her limits as the stakes rise higher than ever.

Now, as Ursula and the Party approach their final stand, the fractured timeline threatens to spiral further out of control. The question remains: how much can Ursula change without losing herself, and will her sacrifices be enough to defeat Vecna once and for all?