diff --git a/src/mapper/mapper.cc b/src/mapper/mapper.cc
index df8e57e..b0c55d5 100644
--- a/src/mapper/mapper.cc
+++ b/src/mapper/mapper.cc
@@ -17,6 +17,7 @@
 
 namespace fallout {
 
+static int bookmarkInit();
 static int bookmarkExit();
 static void bookmarkHide();
 static void bookmarkUnHide();
@@ -50,6 +51,12 @@ unsigned char* tool;
 // 0x6EC4AC
 int tool_win;
 
+// 0x4875B4
+int bookmarkInit()
+{
+    return 0;
+}
+
 // 0x4875B8
 int bookmarkExit()
 {