Adapted from the novel by C.J. Skuse, the drama stars the 'Yellowjackets' alum as a bullied and overlooked young woman who reaches a violent breaking point.

Exactly how far do you have to push a wallflower before she turns into a Venus flytrap? That’s the question at the center of Starz’s Sweetpea, the dark comedy starring Ella Purnel (Yellowjackets, Fallout) that premiered Thursday.

STARZ released a sneak peek at Sweetpea, where Ella Purnell plays a wallflower who blossoms when she starts killing people she hates.

Fallout' star Ella Purnell discusses how she became a producer for the Sky/Starz serial killer comedy 'Sweetpea' and developing her character.

Being dubbed a 'coming-of-rage' story and based on C.J. Skuse's popular novels of the same name, Sweetpea sees the brilliant Ella Purnell ( Yellowjackets, Fallout) transforming Rhiannon from timid wallflower to knife-wielding avenging angel.