diff --git a/src/sleuth.c b/src/sleuth.c
index a677139..d51326a 100644
--- a/src/sleuth.c
+++ b/src/sleuth.c
@@ -5,11 +5,16 @@
 #include <stddef.h>
 
 struct gargoyle_opt *gargoyle_find_brand(uint16_t optc, struct gargoyle_opt *optv, const char *brand, const char *neg, uint16_t neg_sz, gargoyle_flag_type flags) {
+  if(!neg) {
+    neg = "no-";
+    neg_sz = 3;
+  }
+
   for(; optc; optc -= 1, optv += 1) {
     const char *idx = brand;
 
     if(optv->type & GARGOYLE_TYPE_BOOL && gargoyle_cmp(idx, neg, neg_sz, flags)) {
-      idx += 3;
+      idx += neg_sz;
     }
 
     uint8_t end = !*(idx + optv->brand_sz);