Dr. Parker believes he has found the mechanism that keeps the mind intact: invisible "minus tags" that mark thoughts as not-real, not-self, or not-actionable before they reach conscious awareness. When those tags fail, reality does not collapse into madness so much as widen into dangerous possibility.

As his research sharpens, Parker becomes convinced he is uncovering a universal structure of cognition. But the cost of that discovery grows steadily clearer to the people around him—his colleague, his wife Clara, and his daughter Lily.

Set inside a research facility where clinical language and private ruin sound almost the same, The Minus Tag Hypothesis is a psychological literary thriller about sanity, selfhood, family, and the terrifying elegance of an idea that may be true.