diff --git a/src/sdltiles.cpp b/src/sdltiles.cpp
index 6be59ae5fd834..019be0c38c08a 100644
--- a/src/sdltiles.cpp
+++ b/src/sdltiles.cpp
@@ -1077,18 +1077,18 @@ cata::optional<std::pair<tripoint_abs_omt, std::string>> get_mission_arrow(
     int z;
     for( const tripoint &traj_pt : mission_trajectory ) {
         if( !overmap_area.contains( traj_pt ) ) {
-            z = prev.z - traj_pt.z;
+            z = prev->z - traj_pt.z;
             break;
         }
         prev = traj_pt;
     }
 
-    if( prev.z == INT_MAX ) {
+    if( !prev ) {
         debugmsg( "ERROR: trajectory for mission in overmap failed" );
         return cata::nullopt;
     }
 
-    return std::make_pair( tripoint_abs_omt( prev ), mission_arrow_variant );
+    return std::make_pair( tripoint_abs_omt( *prev ), mission_arrow_variant );
 }
 
 int cata_tiles::get_omt_rotation( std::string &id )