In the end, they gave me a conclusion, because a conclusion is what the world requires even when the truth is missing.

It was ruled a boating accident.

A sudden, violent undercurrent, they said; the lake was known for them after heavy rain, treacherous channels where the water moved in ways the surface did not show.

The boat had been caught, or swamped, or thrown against something below, and the four of them had gone into cold water far from shore, and the current had carried them away downstream, which was why nothing had been found.

It was plausible.