Vera is a 60-year-old Chinese mother living in San Francisco. Widowed and lonely, she runs a declining tea shop where she spends her days prescribing specific blends to her only regular customer. When she discovers a dead body on the floor of her shop, her profound boredom transforms into a determined sense of purpose. Certain that the police are incompetent, she confiscates a flash drive from the corpse's hand and begins her own amateur murder investigation, treating her suspects with a blend of intense suspicion and overbearing maternal care.

Julia is a mother trapped in a toxic marriage, left to care for her young daughter, Emma. Her confidence and passion for photography have severely eroded under her husband Marshall's controlling behavior. When Marshall is found dead, Julia becomes one of Vera's primary suspects, though she soon finds herself benefiting from Vera's aggressive household management.

Oliver is Marshall's twin brother and the family's self-described scapegoat. He has spent his life taking the blame for his brother's misdeeds, a dynamic that began when they were children. He works as a building manager and quietly writes a draft of a novel loosely based on his resentment toward his twin.

Riki is a desperate young man trying to achieve financial success to help his younger brother attend a special school. He recently had a tense, physical confrontation with Marshall over an unpaid programming job involving a scam. Riddled with guilt over the altercation, he arrives at the tea shop to gather information and immediately becomes one of Vera's prime suspects.

Sana is an aspiring artist who dropped out of art school and now struggles with severe creative block. She financially relies on her famous mother, whose overbearing support leaves Sana feeling inadequate. She arrives at the tea shop under a false identity to investigate Marshall's death, hiding her own deep resentments regarding how he handled her artwork.

Marshall is a charismatic but deeply cruel man who leaves a wide trail of cheated and hurt people in his wake. He exploits software developers, steals digital rights from artists, and emotionally abuses his immediate family. His sudden death from an apparent allergic reaction sets the plot in motion, drawing all his victims together.

Tilly is Vera's adult son, working as a successful lawyer. He cares for his mother but maintains strict boundaries, finding her constant texts and calls stifling. He operates primarily on American cultural expectations of independence, which frequently clashes with Vera's traditional Chinese expectations of constant filial devotion.

Alex is Vera's longtime friend and the sole regular patron of her business. He frequently visits to chat, drink specially prepared tea, and boast about his highly successful, filial son. His daily presence provides Vera with reliable companionship in her otherwise quiet life.

Emma is Julia and Marshall's young daughter. She is extremely shy due to her father's frequent hostility and her mother's resulting anxious protection. She begins to step out of her shell under the attentive, practical guidance of "Grandma Vera," who treats her with structured respect.

Officer Gray is a pragmatic police officer assigned to Marshall's case. She relies strictly on medical examiner reports, quickly dismissing the death as an accidental allergic reaction to bird dander, which heavily frustrates Vera's desire for a dramatic murder investigation.

Priya is a famous, wealthy writer and Sana's mother. Having been disowned by her own parents for leaving engineering, she overcompensates by providing aggressive, relentless support for Sana's art, creating immense psychological pressure that makes it impossible for her daughter to cope with normal failures.

Adi is Riki's brilliant younger brother who lives abroad. He requires a specialized school that his family cannot afford, driving his brother's desperate attempts to earn large sums of money through questionable programming jobs.