Ella Purnell plays a wallflower-turned-murderer in the official trailer for Sky and Starz’s thriller series “Sweetpea.” The “Yellowjackets” and “Fallout” breakout stars as Rhiannon Lewis, a young woman who doesn’t particularly make an impression,

STARZ has finally unveiled the trailer for Sweetpea, an upcoming “coming-of-rage” thriller series starring Yellowjackets and Fallout’s Ella Purnell as a woman who sometimes likes to make a list of people she’d like to kill.