diff --git a/apps/openmw/mwworld/worldimp.cpp b/apps/openmw/mwworld/worldimp.cpp
index bbc44f5e1..3e23679b1 100644
--- a/apps/openmw/mwworld/worldimp.cpp
+++ b/apps/openmw/mwworld/worldimp.cpp
@@ -190,8 +190,9 @@ namespace MWWorld
             // This parses the ESM file
             ESM::ESMReader lEsm;
             lEsm.setEncoding(encoding);
-            lEsm.open (masterPath.string());
             lEsm.setIndex(idx);
+            lEsm.setGlobalReaderList(&mEsm);
+            lEsm.open (masterPath.string());
             mEsm[idx] = lEsm;
             mStore.load (mEsm[idx]);
         }
@@ -205,8 +206,9 @@ namespace MWWorld
             // This parses the ESP file
             ESM::ESMReader lEsm;
             lEsm.setEncoding(encoding);
-            lEsm.open (pluginPath.string());
             lEsm.setIndex(idx);
+            lEsm.setGlobalReaderList(&mEsm);
+            lEsm.open (pluginPath.string());
             mEsm[idx] = lEsm;
             mStore.load (mEsm[idx]);
         }
diff --git a/components/esm/esmcommon.hpp b/components/esm/esmcommon.hpp
index d61564c67..335d12337 100644
--- a/components/esm/esmcommon.hpp
+++ b/components/esm/esmcommon.hpp
@@ -89,6 +89,7 @@ struct MasterData
 {
   std::string name;
   uint64_t size;
+  int index; // Position of the parent file in the global list of loaded files
 };
 
 // Data that is only present in save game files
diff --git a/components/esm/esmreader.cpp b/components/esm/esmreader.cpp
index 2915a1ce7..d1703a2ac 100644
--- a/components/esm/esmreader.cpp
+++ b/components/esm/esmreader.cpp
@@ -1,5 +1,6 @@
 #include "esmreader.hpp"
 #include <stdexcept>
+#include <boost/filesystem/v3/operations.hpp>
 
 namespace ESM
 {
@@ -61,6 +62,7 @@ void ESMReader::openRaw(Ogre::DataStreamPtr _esm, const std::string &name)
 void ESMReader::open(Ogre::DataStreamPtr _esm, const std::string &name)
 {
     openRaw(_esm, name);
+    std::string fname = boost::filesystem::path(name).filename().string();
 
     if (getRecName() != "TES3")
         fail("Not a valid Morrowind file");
@@ -78,6 +80,29 @@ void ESMReader::open(Ogre::DataStreamPtr _esm, const std::string &name)
         MasterData m;
         m.name = getHString();
         m.size = getHNLong("DATA");
+        // Cache parent esX files by tracking their indices in the global list of
+        //  all files/readers used by the engine. This will greaty help to accelerate
+        //  parsing of reference IDs.
+        size_t index = ~0;
+        // TODO: check for case mismatch, it might be required on Windows.
+        size_t i = 0;
+        // FIXME: This is ugly! Make it nicer!
+        for (; i < idx; i++) {
+            const std::string &candidate = mGlobalReaderList->at(i).getContext().filename;
+            std::string fnamecandidate = boost::filesystem::path(candidate).filename().string();
+            if (m.name == fnamecandidate) {
+                index = i;
+                break;
+            }
+        }
+        if (index == (size_t)~0) {
+            // Tried to load a parent file that has not been loaded yet. This is bad,
+            //  the launcher should have taken care of this.
+            std::string fstring = "File " + fname + " asks for parent file " + m.name
+              + ", but it has not been loaded yet. Please check your load order.";
+            fail(fstring);
+        }
+        m.index = index;
         mMasters.push_back(m);
     }
 
diff --git a/components/esm/esmreader.hpp b/components/esm/esmreader.hpp
index f09442a57..b415009d3 100644
--- a/components/esm/esmreader.hpp
+++ b/components/esm/esmreader.hpp
@@ -83,6 +83,8 @@ public:
   int idx;
   void setIndex(const int index) {idx = index; mCtx.index = index;}
   const int getIndex() {return idx;}
+  
+  void setGlobalReaderList(std::vector<ESMReader> *list) {mGlobalReaderList = list;}
 
   /*************************************************************************
    *
@@ -254,6 +256,7 @@ private:
 
   SaveData mSaveData;
   MasterList mMasters;
+  std::vector<ESMReader> *mGlobalReaderList;
   ToUTF8::FromType mEncoding;
 };
 }
diff --git a/components/esm/loadcell.cpp b/components/esm/loadcell.cpp
index beedd3cac..1a1811a90 100644
--- a/components/esm/loadcell.cpp
+++ b/components/esm/loadcell.cpp
@@ -170,8 +170,6 @@ std::string Cell::getDescription() const
 
 bool Cell::getNextRef(ESMReader &esm, CellRef &ref)
 {
-    // TODO: Add support for multiple plugins. This requires a tricky renaming scheme for "ref.mRefnum".
-    //  I'll probably add something to "ESMReader", we will need one per plugin anyway.
     // TODO: Try and document reference numbering, I don't think this has been done anywhere else.
     if (!esm.hasMoreSubs())
         return false;
@@ -194,6 +192,26 @@ bool Cell::getNextRef(ESMReader &esm, CellRef &ref)
     //  This may require some not-so-small behing-the-scenes updates.
     esm.getHNT(ref.mRefnum, "FRMR");
     ref.mRefID = esm.getHNString("NAME");
+    
+    // Identify references belonging to a parent file and adapt the ID accordingly.
+    int local = (ref.mRefnum & 0xff000000) >> 24;
+    size_t global = esm.getIndex() + 1;
+    if (local)
+    {
+        // If the most significant 8 bits are used, then this reference already exists.
+        // In this case, do not spawn a new reference, but overwrite the old one.
+        ref.mRefnum &= 0x00ffffff; // delete old plugin ID
+        const ESM::ESMReader::MasterList &masters = esm.getMasters();
+        // TODO: Test how Morrowind does it! Maybe the first entry in the list should be "1"...
+        global = masters[local-1].index + 1;
+        ref.mRefnum |= global << 24; // insert global plugin ID
+        std::cout << "Refnum_old = " << ref.mRefnum << " " << local << " " << global << std::endl;
+    }
+    else
+    {
+        // This is an addition by the present plugin. Set the corresponding plugin index.
+        ref.mRefnum |= global << 24; // insert global plugin ID
+    }
 
     // getHNOT will not change the existing value if the subrecord is
     // missing