The story in three lines. Lan and Inkling arrive in a Scottish river valley about ten thousand years ago. A girl there must keep count all winter so her family is at the falls when the salmon come back. Waiting for a warm feeling fails, and a knot for every day half works until the cord turns into a tangle. Counting moons in a row of twelve pits works. Lan's question about the shortest day keeps the count from slipping.

One question to ask. "Why is counting moons easier than counting days?" Then: "Why did they point the pits at the dip in the hills?"

One thing to do at the table. Pick something that comes round again, like the bin day or a weekly club. Make a row of boxes and move a coin along one each time it comes. Ask how many to go just by looking.

The grown-up layer. The idea is a calendar. Things that come round again can be counted, so you can say when they will come back. Twelve moons fall about eleven days short of a year. So a moon count needs something yearly, like the midwinter sunrise, to set it right. This time Inkling says the answer too soon and it buzzes. The Honest Page is careful: the twelve pits at Warren Field are real, and the calendar is how archaeologists explained them in 2013. The people who dug them left no words.