The Ice Queen's Revenge

Summer Shaw, burned to death by her patriarchal family and the Thornes during an apocalyptic heatwave, is reborn twenty days before the disaster. She awakens a Snowflake Sigil, controlling extreme cold, and plots revenge. She sets up her family and fiancé, Titus Thorne, to turn against each other, steals back her embezzled money, and stockpiles supplies in an Air-Raid Shelter, creating the only ice-cold fortress in the apocalypse.