diff --git a/src/biotracker/state.rs b/src/biotracker/state.rs
index fdf7450726aa75aa2185238be2d5b5efaeab4822..2720aa5e3f578ce273298e8add9050b2f805b764 100644
--- a/src/biotracker/state.rs
+++ b/src/biotracker/state.rs
@@ -61,7 +61,7 @@ impl State {
             } else {
                 0
             };
-            let track_frame_number = image.frame_number - track_offset;
+            let track_frame_number = image.frame_number - track_offset + 1;
             if let Some(features) = self.track.features.get(&track_frame_number) {
                 self.experiment.last_features = Some(features.clone());
             }