diff --git a/src/main/java/org/ntlab/acanthus_server/resources/gallery/LayersRest.java b/src/main/java/org/ntlab/acanthus_server/resources/gallery/LayersRest.java
index 88b550c..e0a00e8 100644
--- a/src/main/java/org/ntlab/acanthus_server/resources/gallery/LayersRest.java
+++ b/src/main/java/org/ntlab/acanthus_server/resources/gallery/LayersRest.java
@@ -1,7 +1,9 @@
 package org.ntlab.acanthus_server.resources.gallery;
 
 import org.ntlab.acanthus_server.entities.Layer;
+import org.ntlab.acanthus_server.entities.Page;
 import org.ntlab.acanthus_server.entities.Position;
+import org.ntlab.acanthus_server.entities.Stroke;
 import org.ntlab.acanthus_server.models.Gallery;
 import org.springframework.stereotype.Component;
 
@@ -27,7 +29,12 @@
     @Produces(MediaType.APPLICATION_JSON)
     public Integer getLayers(@PathParam("aid") Integer aid, @PathParam("pid") Integer pid) {
         var pages = gallery.getAnimationByAid(aid).getPages();
-        return pages.get(pid).getLayers().size();
+        for (var p : pages) {
+            if (!p.getPid().equals(pid)) continue;
+            return p.getLayers().size();
+        }
+
+        throw new WebApplicationException(404);
     }
 
 
@@ -40,13 +47,17 @@
     @POST
     @Produces(MediaType.APPLICATION_JSON)
     public Integer addLayer(@PathParam("aid") Integer aid, @PathParam("pid") Integer pid) {
+        var layerSize = 4;
         var pages = gallery.getAnimationByAid(aid).getPages();
+        var page = (Page) null;
 
-        if (pages.get(pid).getLayers().size() < 4) {
-            pages.get(pid).getLayers().add(new Layer());
+        for (var p : pages) {
+            if (!p.getPid().equals(pid)) continue;
+            page = p;
+            if (p.getLayers().size() < layerSize) p.getLayers().add(new Layer());
         }
 
-        return pages.get(pid).getLayers().size();
+        return page.getLayers().size();
     }
 
 
@@ -61,7 +72,11 @@
     @Produces(MediaType.APPLICATION_JSON)
     public Integer getStrokeNo(@PathParam("aid") Integer aid, @PathParam("pid") Integer pid, @PathParam("layerNo") Integer layerNo) {
         var pages = gallery.getAnimationByAid(aid).getPages();
-        var strokes = pages.get(pid).getLayers().get(layerNo).getStrokes();
+        var strokes = new ArrayList<Stroke>();
+        for (var p : pages) {
+            if (pid.equals(p.getPid()))
+                strokes = p.getLayers().get(layerNo).getStrokes();
+        }
 
         if (strokes == null) return null;
         return (strokes.size() - 1);