The Baztán basin is the landscape through which the novel’s crimes, local memories, and competing explanations converge. Its river first appears as part of the domain of a mythic guardian and later emerges on Amaia Salazar’s maps as the line connecting infant deaths across towns and generations. The basin is therefore more than a setting: it is where an unsettling pattern becomes visible, and where the investigation’s rational geography meets the valley’s older language of sacrifice and imbalance.

Geography and the River’s Course

The investigative map follows the Baztán River through settlements including Erratzu, Arraioz, Elbete, and Elizondo, continuing toward Oieregi. The river eventually takes the name Bidasoa; when the team considers records from a wider area, the pattern extends along its course from its source to its mouth. The changing name does not break the investigators’ geographical frame: the waterway supplies a continuous route through the locations under examination.

This geography is not simply a matter of proximity. Amaia initially plots the victims’ home towns against the N-121, a major road that might have offered a serial offender an escape route. But the distribution does not fit that explanation. When she marks the localities anew, the blue line of the river becomes more compelling than the road: the relevant pattern follows the water, not an obvious transport corridor.

A Landscape of Cases and Memory

The valley’s significance reaches beyond the infant deaths. Amaia recalls the girls killed the previous year, human remains left in the mountains and at Cueva de Arri Zahar, and the danger that came close to Ibai. In her reasoning, these are different crimes, but each has disturbed the place in which it occurred. Bodies in the mountains and river are especially charged because those are understood as the domains of forces that preserve the balance between life and death.

The basin also holds an older history of suspected ritual violence. Sarasola describes a group established in 1979 at a farmhouse in Lesaka, where a newborn girl was killed as an offering. Amaia recognizes a near-parallel in Baztán: another infant’s death at a farmhouse, where the parents’ alibi was better prepared and the crime was never investigated. Sarasola connects that location with the grief therapies conducted by Berasategui. The account turns the valley’s past into part of the present inquiry, while leaving the relationship between the historical crimes and the newer cases to be established rather than assumed.

Mapping the Infant Deaths

Amaia’s reconstruction gives the river a practical investigative role. In Jonan’s files, the list of previously investigated crib deaths included Amaia’s own sister, although it omitted Yolanda Berrueta’s children. Amaia adds her sister’s case to the map, marks the towns, and sees that the river-side locations form a line. The shape is not proof of a single cause, but it changes the question: the cases may be connected by place even when the usual model of a road-based offender does not explain them.

The team then broadens its search to records across Navarra and uses baptismal registers to narrow the list. That work is slow because the relevant information must be sought from individual parish priests, who alone can access it and are available only during parish office hours. In Hondarribia, the four possible cases are reduced to two: one girl had died while her parents were on holiday, and another had been baptized. The wider search identifies cases in Elizondo, Oronoz-Mugaire, Narbarte, Doneztebe, and Hondarribia, all in towns adjoining the river.

The accumulated map joins recent cases to older ones. Amaia asks that earlier deaths be marked separately, including the girl from Argi Beltz, her own sister, the girl from Lesaka, the daughter of the lawyers Lejarreta y Andía in Elbete, and the daughter of the father who confronted the forensic doctor in Erratzu. The marks extend along the river to the point where it becomes the Bidasoa. Their disturbing continuity makes the watercourse a working hypothesis: a way to organize cases and direct further investigation, not a conclusion in itself.

Myth and the Disturbed Balance

For Engrasi, the valley’s uncanny dimension is expressed through the Basajaun, understood as guardian of the forest and keeper of the proportion between life and death. She imagines that a grave offense has broken an important balance and forced the being to show itself. The crimes that weigh on her account include the murders of the girls, the killings and abandoned remains associated with the valley, and the danger to Ibai. When she speaks of the river, Amaia echoes the word, turning it into both a physical location and the focus of their unease.

Amaia sets that mythic interpretation beside a broader account of infant deaths during sleep. Engrasi names Inguma, the demon said to steal the breath of sleepers. Amaia notes that accounts of comparable beings occur in many cultures and that patterns of such deaths have at times prompted scientific investigation, including an alert by the Centers for Disease Control in Atlanta. This does not settle whether the valley’s cases are supernatural or criminal. Instead, the contrast sharpens the novel’s central tension: the same repeated deaths can invite folklore, medical explanation, and police scrutiny, while the map offers a concrete way to pursue their connection.

Narrative Significance

The Baztán basin gathers separate strands of the story into one visible form. A map first seems to promise the familiar logic of routes and escape; the riverline overturns that expectation and directs attention toward a less obvious geography. At the same time, the river carries the weight of earlier crimes, local memory, and the language of purification and offense. It joins measurable locations without erasing the uncertainty surrounding them, making the landscape an instrument of inquiry and a source of moral and mythic pressure.