diff --git a/Sources/Plasma/CoreLib/plString.cpp b/Sources/Plasma/CoreLib/plString.cpp
index af59238d..6d11502f 100644
--- a/Sources/Plasma/CoreLib/plString.cpp
+++ b/Sources/Plasma/CoreLib/plString.cpp
@@ -88,14 +88,12 @@ void plString::IConvertFromUtf8(const char *utf8, size_t size)
     operator=(plStringBuffer<char>(utf8, size));
 }
 
-plString &plString::operator=(const plStringBuffer<char> &init)
-{
-    fUtf8Buffer = init;
-
 #ifdef _DEBUG
     // Check to make sure the string is actually valid UTF-8
-    const char *sp = fUtf8Buffer.GetData();
-    while (sp < fUtf8Buffer.GetData() + fUtf8Buffer.GetSize()) {
+static void _check_utf8_buffer(const plStringBuffer<char> &buffer)
+{
+    const char *sp = buffer.GetData();
+    while (sp < buffer.GetData() + buffer.GetSize()) {
         unsigned char unichar = *sp++;
         if ((unichar & 0xF8) == 0xF0) {
             // Four bytes
@@ -115,8 +113,22 @@ plString &plString::operator=(const plStringBuffer<char> &init)
             hsAssert(0, "UTF-8 character out of range");
         }
     }
+}
+#else
+#   define _check_utf8_buffer(buffer)  NULL_STMT
 #endif
 
+plString &plString::operator=(const plStringBuffer<char> &init)
+{
+    fUtf8Buffer = init;
+    _check_utf8_buffer(fUtf8Buffer);
+    return *this;
+}
+
+plString &plString::operator=(plStringBuffer<char> &&init)
+{
+    fUtf8Buffer = std::move(init);
+    _check_utf8_buffer(fUtf8Buffer);
     return *this;
 }
 
diff --git a/Sources/Plasma/CoreLib/plString.h b/Sources/Plasma/CoreLib/plString.h
index 8004d32f..0fb50769 100644
--- a/Sources/Plasma/CoreLib/plString.h
+++ b/Sources/Plasma/CoreLib/plString.h
@@ -128,6 +128,13 @@ public:
             fData->AddRef();
     }
 
+    /** Move constructor */
+    plStringBuffer(plStringBuffer<_Ch> &&move) : fSize(move.fSize)
+    {
+        memcpy(fShort, move.fShort, sizeof(fShort));
+        move.fSize = 0;
+    }
+
     /** Construct a string buffer which holds a COPY of the \a data, up to
      *  \a size characters.  The terminating '\0' is added automatically,
      *  meaning this constructor is safe to use on buffers which are not
@@ -154,7 +161,7 @@ public:
     }
 
     /** Assignment operator.  Changes the reference to point to the
-     *  copied buffer in \a copy.
+     *  buffer in \a copy.
      */
     plStringBuffer<_Ch> &operator=(const plStringBuffer<_Ch> &copy)
     {
@@ -168,6 +175,18 @@ public:
         return *this;
     }
 
+    /** Move assignment operator */
+    plStringBuffer<_Ch> &operator=(plStringBuffer<_Ch> &&move)
+    {
+        if (IHaveACow())
+            fData->DecRef();
+
+        memcpy(fShort, move.fShort, sizeof(fShort));
+        fSize = move.fSize;
+        move.fSize = 0;
+        return *this;
+    }
+
     /** Returns a pointer to the referenced string buffer. */
     const _Ch *GetData() const { return IHaveACow() ? fData->fStringData : fShort; }
 
@@ -235,14 +254,15 @@ private:
     void IConvertFromUtf32(const UniChar *ustr, size_t size);
     void IConvertFromIso8859_1(const char *astr, size_t size);
 
+public:
     // Constructing and comparing with nil or nullptr won't break plString,
     // but it's preferred not to do so with the constants.  That is to say,
     // you can construct with a const char * which points to null, but
     // don't actually write `plString foo = nil;`
-    plString(std::nullptr_t) { }
-    void operator=(std::nullptr_t) { }
-    void operator==(std::nullptr_t) const { }
-    void operator!=(std::nullptr_t) const { }
+    plString(std::nullptr_t) = delete;
+    void operator=(std::nullptr_t) = delete;
+    void operator==(std::nullptr_t) const = delete;
+    void operator!=(std::nullptr_t) const = delete;
 
 public:
     /** Construct a valid, empty string. */
@@ -264,12 +284,18 @@ public:
     /** Copy constructor. */
     plString(const plString &copy) : fUtf8Buffer(copy.fUtf8Buffer) { }
 
+    /** Move constructor. */
+    plString(plString &&move) : fUtf8Buffer(std::move(move.fUtf8Buffer)) { }
+
     /** Copy constructor from plStringBuffer<char>.
      *  \note This constructor expects the input to be UTF-8 encoded.  For
      *        conversion from ISO-8859-1 8-bit data, use FromIso8859_1().
      */
     plString(const plStringBuffer<char> &init) { operator=(init); }
 
+    /** Move constructor from plStringBuffer<char>. */
+    plString(plStringBuffer<char> &&init) { operator=(std::move(init)); }
+
     /** Construct a string from expanded Unicode data. */
     plString(const plUnicodeBuffer &init) { IConvertFromUtf32(init.GetData(), init.GetSize()); }
 
@@ -283,9 +309,15 @@ public:
     /** Assignment operator.  Same as plString(const plString &). */
     plString &operator=(const plString &copy) { fUtf8Buffer = copy.fUtf8Buffer; return *this; }
 
+    /** Assignment operator.  Same as plString(plString &&). */
+    plString &operator=(plString &&move) { fUtf8Buffer = std::move(move.fUtf8Buffer); return *this; }
+
     /** Assignment operator.  Same as plString(const plStringBuffer<char> &). */
     plString &operator=(const plStringBuffer<char> &init);
 
+    /** Assignment operator.  Same as plString(plStringBuffer<char> &&). */
+    plString &operator=(plStringBuffer<char> &&init);
+
     /** Assignment operator.  Same as plString(const plUnicodeBuffer &). */
     plString &operator=(const plUnicodeBuffer &init) { IConvertFromUtf32(init.GetData(), init.GetSize()); return *this; }
 
@@ -685,6 +717,27 @@ public:
     /** Destructor, frees any allocated heap memory owned by the stream. */
     ~plStringStream() { if (ICanHasHeap()) delete [] fBuffer; }
 
+    plStringStream(const plStringStream &) = delete;
+    plStringStream &operator=(const plStringStream &) = delete;
+
+    /** Move operator */
+    plStringStream(plStringStream &&move)
+        : fBufSize(move.fBufSize), fLength(move.fLength)
+    {
+        memcpy(fShort, move.fShort, sizeof(fShort));
+        move.fBufSize = 0;
+    }
+
+    /** Move assignment operator. */
+    plStringStream &operator=(plStringStream &&move)
+    {
+        memcpy(fShort, move.fShort, sizeof(fShort));
+        fBufSize = move.fBufSize;
+        fLength = move.fLength;
+        move.fBufSize = 0;
+        return *this;
+    }
+
     /** Append string data to the end of the stream. */
     plStringStream &append(const char *data, size_t length);