Serpent’s Sacrifice by Trish Heinrich

Being a hero could cost her everything.
Ever since Alice was saved from her abusive father, she’s wanted to be a hero. But in 1960’s Jet City, women are supposed to want marriage and babies, not cowls and secret identities.
When her beloved aunt is murdered by a new crime syndicate, Alice takes up the mantle of the Serpent, a heroine who has been protecting Jet City for decades.
But one mistake will unleash a dreadful villain. One who will stop at nothing to take control of the city and kill anyone who stands in the way.