Rita Salvatore is the twin and half-sister of Damon Salvatore and a daughter of Poseidon. When Damon's plan to get into the tomb go off the rails, he turns to his sister to aid him which leads to Rita returning to Mystic Falls. Whilst home, Rita starts developing feelings for the local vampire hunter, Alaric but things are never easy in the world of vampires and humans. Both struggle to come to terms with their feelings whilst they battle the threats around them. - Whilst not a full crossover, this will have elements of Riordan's demi-god world and Doctor Who.