When worlds collide (a Percy Jackson and Harry Potter crossover)

Elizabeth, Roman daughter of Neptune, is called to the Big House. Along with the seven, Nico, Sandra, Reyna and Rachel. Chiron tells them of a magical school in England, and says that they must go there. In England, Harry Potter and his friends are getting ready to redo there 7th year. When they meet the demigods, Harry starts to think they're up to no good. Will Harry unmask them? Or will the demigods form an alliance with the wizards just in time.