Back at the mansion, we have the reading of the will - or at least a holographic recording that Xavier had made, shortly before going off to confront Grotesk. He reveals what he says was the real secret of X-Men #41-#42 - that he'd been training Jean in telepathy (she had been strictly telekinesis only until now).
We discover that Wanda has been depowered, and that Pietro and Wanda are hoping Magneto will be able to fix this. Magneto has also someone managed to sucker Toad into joining up, despite abandoning Toad on an alien planet. They've nearly got the whole gang back together again... But Magneto has a secret - he caused Wanda's depowerment in the first place!
The X-Men try to Trojan horse Magneto, but get captured, and all placed in custom prisons. Angel escapes, though, and goes away to New York City to fetch the Avengers, stopping off en route during issue #44 to have a side story with Red Raven, a Timely character from the 1940s. The Avengers team he meets is the Hawkeye/Black Panther/Giant-Man/Wasp line-up, just after Black Panther joined, and before they encountered The Vision.
Magneto has a plan. Firstly, as he has outlined, he wishes to create a "sanctuary... a separate country for mutants", on a small island. Scott sees "a lot of sense in what he's saying." But the rest of the plan, which sets the Avengers and X-Men against each other in a big fight, young Mr Summers is less keen on. Magneto is revealed to have let Warren escape, and planted a bug on him, leading to the Avengers believing the X-Men have betrayed them and joined the Brotherhood. Except, at the least moment, we discover that the Avengers have out-thought Magneto. We end Avengers #53 with the Avengers triumphant, and Pietro and Wanda running away on their own again...
All in all, this is very confused, with shifting motivations and no sense of who knows what when, and so therefore it's no surprise to learn that the writer changed during this, from Roy Thomas to Gary Friedrich. The X-Men have permanently lost Xavier, which ought to be opening new story pastures, but instead we get a story which is fundamentally quite regressive, with the artificial return of old Brotherhood line-up only to have Wanda and Pietro break away, a story that we have done pretty much exactly like that before. Additionally, Angel's side story jars, and I suspect it of being inventory material being worked into the ongoing plot somehow.