Lock Four is the place where Isaac remembers his mother’s body being found in the river, not the place where anyone knows she entered it. Seen from the opposite bank while he is walking at night, the lock turns a distant industrial landmark into the point where an unresolved family loss becomes concrete—and where Isaac confronts his own past preoccupation with the weight of the stones in her pockets.

Setting and Identification

Isaac sees the cranes across the river from Charleroi and initially takes them to mark Lock Four. As he approaches, the familiar industrial outline gives way to a specific memory: this is where his mother was discovered, in the lock channel. The pale cement walls had made her visible by contrast, although the river had carried her to the place where she was found.

The distinction between where she entered the water and where she came out remains unresolved. No one knew where she had gone in; the location of her recovery was what the family could identify. Isaac recalls that Lee told him about the discovery, but still wonders how she knew. The lock is therefore both a real point on his route and the limit of what the family knows about her final passage through the river.

What the Discovery Established

His recollection moves from the recovery site to the account of his mother’s death. She had been missing for two weeks. The old man was certain she had been murdered by skinheads, but the autopsy established that she had drowned. The lock’s channel had yielded a location and an explanation of death, but not an answer to every question surrounding her disappearance.

The stones in her coat pockets sharpen that uncertainty into a weight Isaac can measure. There were eleven pounds of them. He remembers making his own estimate by filling his pockets with field stones and checking the scale; he also remembers the old man catching him weighing himself. Isaac’s calculation that the stones could pull anyone under, even Poe, turns private grief into an attempt to understand the physical force of what happened.

Memory and Significance

At the river, the account becomes personal rather than merely forensic. Isaac imagines his mother walking along the water, collecting stones and humming, and recognizes that she had carried pain of her own. His thought that she should be let off does not resolve the mystery of her death; instead, it changes the emphasis from assigning blame to acknowledging suffering.

Lock Four thus gathers several kinds of evidence without making them equivalent: the known place where his mother was found, the autopsy’s conclusion, the unexplained point where she entered the river, and Isaac’s remembered experiment with the stones. As he continues walking, the landmark interrupts his effort to put distance between himself and the past. Its importance lies in that collision of geography and memory: the river offers a discoverable endpoint, while the circumstances that led there remain partly unknown.