diff --git a/internal/handlers/opds.go b/internal/handlers/opds.go
index 1827ab6..84b0764 100644
--- a/internal/handlers/opds.go
+++ b/internal/handlers/opds.go
@@ -402,7 +402,11 @@ func (h *OPDSHandler) DownloadBook(c echo.Context) error {
 			}
 		} else {
 			if h.conversionService != nil {
-				converted, err := h.conversionService.ConvertEPUBToKEPUB(c.Request().Context(), pgtype.UUID{Bytes: bookUUID, Valid: true}, mediaItem.FilePath)
+				resolvedPath, err := h.libraryService.ResolveMediaPath(c.Request().Context(), mediaItem.LibraryID, mediaItem.FilePath)
+				if err != nil {
+					return c.JSON(http.StatusNotFound, map[string]string{"error": "file not found"})
+				}
+				converted, err := h.conversionService.ConvertEPUBToKEPUB(c.Request().Context(), pgtype.UUID{Bytes: bookUUID, Valid: true}, resolvedPath)
 				if err != nil {
 					return c.JSON(http.StatusInternalServerError, map[string]string{"error": fmt.Sprintf("KEPUB conversion failed: %v", err)})
 				}
@@ -410,7 +414,10 @@ func (h *OPDSHandler) DownloadBook(c echo.Context) error {
 				fileSha256 = converted.SHA256
 				mimeType = "application/vnd.kobo+xml+zip"
 			} else {
-				filePath = mediaItem.FilePath
+				filePath, err = h.libraryService.ResolveMediaPath(c.Request().Context(), mediaItem.LibraryID, mediaItem.FilePath)
+				if err != nil {
+					return c.JSON(http.StatusNotFound, map[string]string{"error": "file not found"})
+				}
 				if mediaItem.MimeType.Valid {
 					mimeType = mediaItem.MimeType.String
 				}
@@ -435,7 +442,11 @@ func (h *OPDSHandler) DownloadBook(c echo.Context) error {
 		}
 	} else {
 		// Default: EPUB
-		filePath = mediaItem.FilePath
+		var err error
+		filePath, err = h.libraryService.ResolveMediaPath(c.Request().Context(), mediaItem.LibraryID, mediaItem.FilePath)
+		if err != nil {
+			return c.JSON(http.StatusNotFound, map[string]string{"error": "file not found"})
+		}
 		if mediaItem.MimeType.Valid {
 			mimeType = mediaItem.MimeType.String
 		}