An alien from another dimension comes to Earth as a high-gravity location that will assist his recovery. He knows and fully intends to keep the rules about avoiding contact with those primitive humans, which can be dangerous to them, but he promises a friend to observe them at a safe distance.
Then he falls asleep one day in a glacial lake, and is seen.
Complications follow, thickly. The retrospective account allows him to cover the years that ensue briskly, as he keeps trying to fix things and often faces graver consequences, and puts more humor into it.