Who is Nina Wrigley from Wherever Nina Lies and what is their importance?

Nina Wrigley is the older sister of Ellie Wrigley, whose disappearance sets the stage for the events in the novel "Wherever Nina Lies" by Lynn Weingarten. She is beautiful, artistic, and dyes her hair different colors to match events in her life. She meets Jason, begins dating him, and Jason introduces her to his stepbrother Sean, who develops a crush on Nina. When Nina rejects Sean's love, Sean murders Jason, and Nina flees across the country to San Francisco to keep her family safe. In San Francisco, Nina designs and sells T-shirts and is overjoyed to reunited with Ellie and her mother.