diff --git a/src/lib/plot.c b/src/lib/plot.c
index 534bf228a..f3107437d 100644
--- a/src/lib/plot.c
+++ b/src/lib/plot.c
@@ -101,8 +101,8 @@ window_slide(ncplot* n, uint64_t x){
 // x must be within n's window
 static inline void
 update_sample(ncplot* n, uint64_t x, int64_t y, bool reset){
-  uint64_t delta = x - n->slotx;
-  uint64_t idx = (n->slotstart + delta) % n->slotcount;
+  uint64_t idx = x/*(n->slotstart + delta)*/ % n->slotcount;
+fprintf(stderr, "WRITING %jd to IFX %ju (DELTA: %ju, SLOTX: %ju)\n", y, idx, 0, n->slotx);
   if(reset){
     n->slots[idx] = y;
   }else{
diff --git a/tests/plot.cpp b/tests/plot.cpp
index ae79b0309..185c85dde 100644
--- a/tests/plot.cpp
+++ b/tests/plot.cpp
@@ -60,19 +60,19 @@ TEST_CASE("Plot") {
     ncplot* p = ncplot_create(n_, &popts);
     REQUIRE(p);
     CHECK(0 == p->slots[0]);
-    ncplot_add_sample(p, 0, 1);
+    CHECK(0 == ncplot_add_sample(p, 0, 1));
     CHECK(1 == p->slots[0]);
-    ncplot_add_sample(p, 0, 1);
+    CHECK(0 == ncplot_add_sample(p, 0, 1));
     CHECK(2 == p->slots[0]);
     CHECK(0 == p->slots[1]);
     CHECK(0 == p->slots[2]);
-    ncplot_add_sample(p, 2, 3);
+    CHECK(0 == ncplot_add_sample(p, 2, 3));
     CHECK(3 == p->slots[2]);
-    ncplot_set_sample(p, 2, 3);
+    CHECK(0 == ncplot_set_sample(p, 2, 3));
     CHECK(3 == p->slots[2]);
     CHECK(0 == p->slots[3]);
     CHECK(0 == p->slots[4]);
-    ncplot_add_sample(p, 4, 6);
+    CHECK(0 == ncplot_add_sample(p, 4, 6));
     CHECK(6 == p->slots[4]);
     CHECK(2 == p->slots[0]);
     CHECK(0 == p->slotx);
@@ -88,26 +88,61 @@ TEST_CASE("Plot") {
     ncplot* p = ncplot_create(n_, &popts);
     REQUIRE(p);
     CHECK(0 == p->slots[0]);
-    ncplot_add_sample(p, 0, 1);
+    CHECK(0 == ncplot_add_sample(p, 0, 1));
     CHECK(1 == p->slots[0]);
-    ncplot_add_sample(p, 0, 1);
+    CHECK(0 == ncplot_add_sample(p, 0, 1));
     CHECK(2 == p->slots[0]);
-    ncplot_set_sample(p, 1, 5);
+    CHECK(0 == ncplot_set_sample(p, 1, 5));
     CHECK(5 == p->slots[1]);
-    ncplot_set_sample(p, 2, 9);
+    CHECK(0 == ncplot_set_sample(p, 2, 9));
     CHECK(5 == p->slots[1]);
     CHECK(9 == p->slots[0]);
-    ncplot_add_sample(p, 3, 4);
+    CHECK(0 == ncplot_add_sample(p, 3, 4));
     CHECK(9 == p->slots[0]);
     CHECK(4 == p->slots[1]);
     CHECK(2 == p->slotx);
-    ncplot_add_sample(p, 5, 1);
+    CHECK(0 == ncplot_add_sample(p, 5, 1));
     CHECK(0 == p->slots[0]);
     CHECK(1 == p->slots[1]);
     CHECK(4 == p->slotx);
     ncplot_destroy(p);
   }
 
+  // augment past the window, ensuring everything gets zeroed
+  SUBCASE("AugmentLong"){
+    ncplot_options popts{};
+    popts.rangex = 5;
+    popts.maxy = 10;
+    popts.miny = 0;
+    ncplot* p = ncplot_create(n_, &popts);
+    REQUIRE(p);
+    for(int x = 0 ; x < 5 ; ++x){
+      CHECK(0 == p->slots[x]);
+    }
+    CHECK(0 == ncplot_add_sample(p, 4, 4));
+    for(int x = 0 ; x < 4 ; ++x){
+      CHECK(0 == p->slots[x]);
+    }
+    CHECK(4 == p->slots[4]);
+    CHECK(0 == ncplot_add_sample(p, 10, 5));
+fprintf(stderr, "SLOT 0: %ju\n", p->slots[0]);
+    CHECK(5 == p->slots[0]);
+    for(int x = 1 ; x < 4 ; ++x){
+fprintf(stderr, "SLOT %d: %ju\n", x, p->slots[x]);
+      CHECK(0 == p->slots[x]);
+    }
+    CHECK(0 == ncplot_add_sample(p, 24, 7));
+    for(int x = 0 ; x < 4 ; ++x){
+      CHECK(0 == p->slots[x]);
+    }
+    CHECK(7 == p->slots[4]);
+    CHECK(0 == ncplot_add_sample(p, 100, 0));
+    for(int x = 0 ; x < 5 ; ++x){
+      CHECK(0 == p->slots[x]);
+    }
+    ncplot_destroy(p);
+  }
+
   CHECK(0 == notcurses_stop(nc_));
   CHECK(0 == fclose(outfp_));
 }