Harry in distress Let's all answer his S.O.S

AVADA KEDAVRA!

There was another green light and a rushing sound.

It was at that point that his grip on his broom failed. He fell. And as he did, helpless and in truly mortal danger for the first time in his life, unable to do anything to save himself, something... shifted. His unconscious mind sent out a wordless scream for help, from someone, anyone.

For most, this would have had no effect whatsoever. Even for Harry, it would normally not have achieved a blessed thing. But this time, something in his mind flickered and stirred, like a banked ember at a campfire being prodded into life. His descent slowed, and the psychic SOS went winging away into the aether.

OoOoO

Not a moment later, in Asgard, worlds away, Loki sat bolt upright in his bed, simultaneously very awake, very worried, and very confused. It should have been impossible for such a distress call, aimlessly flung into the void, to reach him. By all logic, it should be impossible, even for this child. For his nephew.

He had known, he grumbled internally as he vaulted out of bed, clothes forming around him. Oh yes, he had known that this would come back to haunt them. He had known that it could not be kept secret forever, indeed, he had opposed the lies in the first place. He had recognised their necessity, yes, but he felt that something should have been done. But had he been listened to? No. No, he hadn't. And now he was going to have to deal with the fall-out.

—- Chapter 1, When Everything Changes