What if Harry knew about Malfoy's plan to smuggle in Death Eaters using the Vanishing Cabinet beforehand? He tells Professor Dumbledore and Professor McGonagall, will they listen? Or will they ignore him and think of it as Harry's rivalry with Malfoy?

It's the beginning of the end of the war. Voldemort is at Hogwarts with all his of his Death Eaters. He speaks, taunts, and argues with both Harry Potter and Albus Dumbledore. Albus also makes sure Minerva McGonagall stays out of sight of the fighting. Why is that?