Big Three to the Rescue

The Big Three demigods have to travel to Hogwarts and befriend the wizards, repair the old conflict between demigods and wizards, earn their trust, and stand together to fight the big battle with Lord Voldemort. Are the demigods capable of that? Because if not, the wizards will lose the war without the help of the demigods. All is at stake. Post Giant War and battle of Hogwarts.