The sea went out on a Tuesday and did not come back.

In Hallow Bay the tide keeps the calendar. Boats are launched by it, the school bell is rung by it, and every death in the parish register is written down beside the height of the water. So when the sea draws back past the last marker and stays there — a mile of wet sand, a drowned road, a church bell sitting in the mud — the town does what towns do. It waits.

Wren Hallett has come home to bury her father, the harbor master, whose tide tables were never wrong. On the third morning of the low water she finds his last entry, dated a week after he died. Now the flats are giving up what the sea kept, and everyone in Hallow Bay has a reason to want it covered again before the water returns.