The fishing boat chartered by the public prosecutor's office left Mazara del Vallo at half past four, before the sun raised the wind. The name of the boat was San Vito, and it belonged to an owner from Trapani who rented it out to the forensic teams for two thousand two hundred euros a day plus fuel, a figure that had already been agreed two years earlier and that had become habitual, as other things had become habitual within the same turn of years: the type of drysuits issued, the orange colour of the evidence tapes, the brand of mineral water that Sergio bought at the port, always the same one, a cheap brand from the Sicilian interior which, according to Sergio, had the advantage of tasting of water.

Anna had been a forensic diver for seven seasons. The figure of seven seasons was one of those figures that, said in a row — seven, eight, nine — turned into something else: they stopped being a count of time gone by and began to be the description of a trade, the way one says of a baker that he works from three, or of a nurse that he has three nights a week. Seven seasons meant that Anna knew the bed of the Strait of Sicily better than she had ever known the bottom of the swimming pool in Avellino where she had learned to swim at six, where there had happened, at the end of her seventh year of age, the thing she had learned not to look at and which on certain days, going down into the cold current off Lampedusa, came back to her, not as an image but as a temperature — the way the water had closed over the ears of her sister Marta, who was nine, while her father was drying his hands on a blue towel that was not big enough.

The procedure for shape number one was this: the body was found, an orange evidence tape was fastened to the cylinder (forty centimetres long, folded in three), the shape was photographed with the Nikonos camera from twenty metres, photographed a second time from five metres, one came up to the ten metres of the decompression stop, one told Sergio over the line that shape number one had been marked, and Sergio wrote in the register: position, time, depth. Shape number two followed the same procedure. Number three. Number four. Anna counted under her breath inside the regulator, a voice that inside the mask was like the voice with which children pray under the blankets — a voice for oneself.

At forty metres down, under the San Vito at seven in the morning, Anna begins to count. Visibility is three metres. The wreck of the fishing boat Karim lies on its right side. The net of the hold is torn. The shapes are caught in the net, on the steps, on the wooden hinges of the hold. Anna marks them with the orange tapes the way books are marked on the shelves of a library to show which ones have been returned.

One. Two. Three. Four. Five. Six.

Seven is the boy.

The boy is — Anna sees him in profile, the light of the head torch lighting the left side of his body — seven or eight years old. The little backpack is of blue oilcloth, with a faded print that Anna recognizes from her nieces' drawings: it is a character from a Japanese cartoon, a sort of white mouse with pointed whiskers. The backpack is still attached to the boy by a single strap, the other strap has torn. The backpack floats a little in the water, like a slack flag behind a pole. Inside the backpack there is something bulky.

Anna has to lift the boy with her hands so as not to damage the remains. The procedure says: two hands under the chest, lift calmly, let the current act as a brake, place the orange tape on the one strap still attached. Anna brings her hands close. One under the chest, the other under the pelvis.

Her right hand stays under him for a second. Then two. Then three.

Anna stops counting.

She has not decided it. It is happening. The voice inside the regulator, which up to six had been a voice for oneself, is gone. There is no seven. There is no thought of seven. There is Anna's right hand under the boy's chest, which does not move. The boy has his eyes closed. His hair is dark and very short, cut not long ago. Not at Lampedusa. From before.

Marco is on the other side of the wreck, seven or eight metres away. Marco has four seasons, he is good, his suits are his own size. Marco does not see Anna. Anna could stay like this — one hand under the boy's chest — for a minute, two, and Marco would not notice. Three minutes, and Sergio from the surface would ask over the line whether there was something. Four minutes, and Marco would come to see.

Anna stays like this for a second. Perhaps two. Then her hands do their part: lift, calm, current. She places the orange tape on the strap. She comes up to ten metres for the stop.

To Sergio, over the line, she says: seven marked.

To Marco, on the surface, on the launch heading for the quay, she says nothing. She drinks from the flask Sergio passes her, a water of a cheap brand from the Sicilian interior that has the advantage of tasting of water. The suits are already in the black bags on deck. The quay at Mazara del Vallo is still, hot, with an Italian flag hanging on its pole.

Sergio passes her the flask. Anna drinks. Then she says quietly:

"Tomorrow I'll do it myself again."

Sergio nods. He does not ask what.