I'm guessing they use a wood fire to heat water for the showers. Day one they used all the kindling too early so they had to have cold showers
Day two - they have a lovely fire going and have hot water. But they are still not going to enjoy a nice long shower because of 'a certain oversight' - something they have forgotten to do or bring. I don't know what without reading the whole thing....perhaps the water is now TOO hot (90 degrees) or maybe there is some other reason the showers will not be pleasant.