Lorelli and Ovid Thornthwaite are not like most 13-year-old children. They live in a huge and creepy mansion, they don't go to school and are heirs to a vast fortune. But what makes the twins even more unusual is their determination to kill each other! When their murderous sibling rivalry is called off it soon becomes clear that one of them can't stop trying to kill the other. But who is really causing the trouble and will they both survive to find out where the real danger lies?