She had filled a notebook page with the symbol—simplifying it even further, abstracting it to just a part of a circle, with a wedge or a line pointing downward. Downward? Would the octopus perceive it as downward? Most likely. Even though the element it existed in was more fluid than ours, the octopus was more subject to gravity than a fish. It was not much of a swimmer. It walked, hunted, grazed on the sea bottom, along rocks and reefs. When threatened, it raised itself up, like a human drawing erect, like an ape swelling its chest and rising on its arms. Like a bear on its hind legs. So yes—there should be, in its world, a down and an up.

But was the wedge pointing down?

And was it a wedge, an arrow, a line?

The symbol, clearly a warning or a threat, nagged at her. She felt as if at some level she already understood it. Had seen it before.

Trees blurred the edge of the road to the port, reclaiming space for themselves. The pavement was scattered with leaves and the husks of seedpods. Monkeys and morning birds screamed from the canopy branches.

The port of Ben Dam had been little more than a small jetty and a cluster of warehouses and shops crammed along a single street. In tourist pictures, the jetty was always lined with women hawking fish from shallow baskets against a background of colorful fishing boats. The tiny port was in a bay shaped like a V, with its sharp tip pointed to the southeast and its open end facing northwest. At the southwestern tip, nearest the abandoned hotel, was a small channel, often filled with tidal surges and treacherous currents. The northwestern end, on the other hand, was nearly a mile wide.

The “bay” was not, in fact, a bay: it was a channel between the island of Con Son, the main island of the Con Dao Archipelago, to the east, and the uninhabited forested hump of Hon Ba to the west.

Here, the damage done by the evacuation was more apparent than it was in the silent, shuttered houses of Con Son Town that Ha had passed through on the night of her arrival. Con Son Town had looked almost peaceful, as if its inhabitants had simply drifted away. But here, sunken fishing boats studded the bay. Wrecks, including a large passenger ferry, were seeded across the entrances to the harbor to render them impassable.

Ha had been here. Sixteen. The hydrofoil journey over the water from Vung Tau had been a blur: She had been watching the boy she loved. Watching him chat with the other boys, watching him look out the window at the green warp of sea, watching him read.