In July 2208, a commercial salvage operation conducting a routine sonar survey approximately 15 kilometers off the shore of Waukegan, Illinois, detected an anomalous formation on the Lake Michigan lakebed at a depth of 87 meters. The formation consisted of sealed containers arranged in a precise grid pattern. The grid was rectangular — twelve containers by eight, for a total of ninety-six units — with uniform spacing of exactly 2 meters between each container. The containers were approximately 1.5 meters long, 0.8 meters wide, and 0.6 meters deep. They appeared to be constructed from a metallic alloy that resisted identification by the salvage team's remote analysis equipment.

The containers were warm. Thermal imaging from the salvage operation's submersible registered a surface temperature of approximately 30 degrees Celsius on every container — uniform, consistent, and significantly above the ambient water temperature of 4 degrees at that depth. This implies an internal heat source. The containers were sealed with no visible seams, hinges, latches, or access points. Their surfaces were smooth and free of biological fouling — no algae, no sediment accumulation, no zebra mussel colonization — despite sitting on a lake bed where every other surface is covered in biological growth within weeks of submersion.

The salvage team documented the array and surfaced to file a report and request authorization for a closer investigation. When a second dive was conducted six days later, the array had been rearranged. The same containers — confirmed by dimensional analysis and thermal signature — were now in a different configuration: ten by ten, minus four corner positions, forming a grid with truncated corners. The spacing had changed to 2.3 meters. The containers had moved, or been moved, on the lake bed. The sediment beneath them showed no drag marks.

Nobody opened one. The salvage team's report notes this decision without elaboration — simply that "no attempt was made to breach or recover any container." No third dive was commissioned. The salvage company's contract for the survey area was not renewed. Subsequent sonar passes of the location by other operators have returned normal lake bed readings with no anomalous formations. The array is either gone, or it has arranged itself in a way that sonar cannot detect, or it was never there in a way that bears repeating.