diff --git a/LEGO1/mxdsaction.cpp b/LEGO1/mxdsaction.cpp
index cccea39c..536fbd8a 100644
--- a/LEGO1/mxdsaction.cpp
+++ b/LEGO1/mxdsaction.cpp
@@ -96,8 +96,8 @@ void MxDSAction::Deserialize(char **p_source, MxS16 p_unk24)
 
   this->m_flags = *(MxU32*) *p_source;
   *p_source += sizeof(MxU32);
-  this->m_startTime = *(DWORD*) *p_source;
-  *p_source += sizeof(DWORD);
+  this->m_startTime = *(MxLong*) *p_source;
+  *p_source += sizeof(MxLong);
   this->m_duration = *(MxLong*) *p_source;
   *p_source += sizeof(MxLong);
   this->m_loopCount = *(MxS32*) *p_source;
diff --git a/LEGO1/mxdsaction.h b/LEGO1/mxdsaction.h
index 265f0a6f..0140390b 100644
--- a/LEGO1/mxdsaction.h
+++ b/LEGO1/mxdsaction.h
@@ -53,6 +53,7 @@ class MxDSAction : public MxDSObject
   inline void SetFlags(MxU32 m_flags) { this->m_flags = m_flags; }
   inline char *GetExtraData() { return m_extraData; }
   inline MxU16 GetExtraLength() const { return m_extraLength; }
+  inline MxLong GetStartTime() const { return m_startTime; }
   inline const MxVector3Data &GetLocation() const { return m_location; }
   inline void SetOmni(MxOmni *p_omni) { m_omni = p_omni; }
 
@@ -61,7 +62,7 @@ class MxDSAction : public MxDSObject
 private:
   MxU32 m_sizeOnDisk;
   MxU32 m_flags;
-  DWORD m_startTime;
+  MxLong m_startTime;
 
 protected:
   MxLong m_duration;
diff --git a/LEGO1/mxdsactionlist.cpp b/LEGO1/mxdsactionlist.cpp
index 86c75365..46eb4e36 100644
--- a/LEGO1/mxdsactionlist.cpp
+++ b/LEGO1/mxdsactionlist.cpp
@@ -2,6 +2,7 @@
 #include "mxdsaction.h"
 
 DECOMP_SIZE_ASSERT(MxDSActionList, 0x1c);
+DECOMP_SIZE_ASSERT(MxDSActionListCursor, 0x10);
 
 // OFFSET: LEGO1 0x100c9c90
 MxS8 MxDSActionList::Compare(MxDSAction *p_var0, MxDSAction *p_var1)
diff --git a/LEGO1/mxdsmediaaction.h b/LEGO1/mxdsmediaaction.h
index f3c03839..cc710425 100644
--- a/LEGO1/mxdsmediaaction.h
+++ b/LEGO1/mxdsmediaaction.h
@@ -34,6 +34,7 @@ class MxDSMediaAction : public MxDSAction
   void CopyMediaSrcPath(const char *p_mediaSrcPath);
 
   inline MxS32 GetMediaFormat() const { return this->m_mediaFormat; }
+  inline MxLong GetSustainTime() const { return this->m_sustainTime; }
 private:
   MxU32 m_sizeOnDisk;
   char *m_mediaSrcPath;
diff --git a/LEGO1/mxdsmultiaction.h b/LEGO1/mxdsmultiaction.h
index 7d4312f4..4900aa2e 100644
--- a/LEGO1/mxdsmultiaction.h
+++ b/LEGO1/mxdsmultiaction.h
@@ -30,6 +30,8 @@ class MxDSMultiAction : public MxDSAction
 
 private:
   MxU32 m_sizeOnDisk;
+
+protected:
   MxDSActionList *m_actions;
 };
 
diff --git a/LEGO1/mxdsserialaction.cpp b/LEGO1/mxdsserialaction.cpp
index c6aa541f..7196b1b7 100644
--- a/LEGO1/mxdsserialaction.cpp
+++ b/LEGO1/mxdsserialaction.cpp
@@ -1,16 +1,80 @@
 #include "mxdsserialaction.h"
+#include "mxdsmediaaction.h"
 
 DECOMP_SIZE_ASSERT(MxDSSerialAction, 0xa8)
 
 // OFFSET: LEGO1 0x100ca9d0
 MxDSSerialAction::MxDSSerialAction()
 {
-  // TODO
   this->SetType(MxDSType_SerialAction);
+  this->m_cursor = new MxDSActionListCursor(this->m_actions);
+  this->m_unk0xa0 = 0;
 }
 
-// OFFSET: LEGO1 0x100cac10 STUB
+// OFFSET: LEGO1 0x100caac0
+void MxDSSerialAction::SetDuration(MxLong p_duration)
+{
+  this->m_duration = p_duration;
+}
+
+// OFFSET: LEGO1 0x100cac10
 MxDSSerialAction::~MxDSSerialAction()
 {
-  // TODO
+  if (this->m_cursor)
+    delete this->m_cursor;
+
+  this->m_cursor = NULL;
 }
+
+// OFFSET: LEGO1 0x100cac90
+void MxDSSerialAction::CopyFrom(MxDSSerialAction &p_dsSerialAction)
+{
+}
+
+// OFFSET: LEGO1 0x100caca0
+MxDSSerialAction &MxDSSerialAction::operator=(MxDSSerialAction &p_dsSerialAction)
+{
+  if (this == &p_dsSerialAction)
+    return *this;
+
+  MxDSMultiAction::operator=(p_dsSerialAction);
+  this->CopyFrom(p_dsSerialAction);
+  return *this;
+}
+
+// OFFSET: LEGO1 0x100cacd0
+MxDSAction *MxDSSerialAction::Clone()
+{
+  MxDSSerialAction *clone = new MxDSSerialAction();
+
+  if (clone)
+    *clone = *this;
+
+  return clone;
+}
+
+// OFFSET: LEGO1 0x100cad60
+MxLong MxDSSerialAction::GetDuration()
+{
+  if (this->m_duration)
+    return this->m_duration;
+
+  MxDSActionListCursor cursor(this->m_actions);
+  MxDSAction *action;
+
+  while (cursor.Next(action)) {
+    if (!action)
+      continue;
+
+    this->m_duration += action->GetDuration() + action->GetStartTime();
+
+    if (action->IsA("MxDSMediaAction")) {
+      MxLong sustainTime = ((MxDSMediaAction*) action)->GetSustainTime();
+
+      if (sustainTime && sustainTime != -1)
+        this->m_duration += sustainTime;
+    }
+  }
+
+  return this->m_duration;
+}
\ No newline at end of file
diff --git a/LEGO1/mxdsserialaction.h b/LEGO1/mxdsserialaction.h
index 6bf30c0f..e2f6cd72 100644
--- a/LEGO1/mxdsserialaction.h
+++ b/LEGO1/mxdsserialaction.h
@@ -12,6 +12,9 @@ class MxDSSerialAction : public MxDSMultiAction
   MxDSSerialAction();
   virtual ~MxDSSerialAction() override;
 
+  void CopyFrom(MxDSSerialAction &p_dsSerialAction);
+  MxDSSerialAction &operator=(MxDSSerialAction &p_dsSerialAction);
+
   // OFFSET: LEGO1 0x100caad0
   inline virtual const char *ClassName() const override // vtable+0x0c
   {
@@ -25,7 +28,12 @@ class MxDSSerialAction : public MxDSMultiAction
     return !strcmp(name, MxDSSerialAction::ClassName()) || MxDSMultiAction::IsA(name);
   }
 
-  undefined4 m_unk0x9c;
+  virtual MxLong GetDuration(); // vtable+24;
+  virtual void SetDuration(MxLong p_duration); // vtable+28;
+  virtual MxDSAction *Clone(); // vtable+2c;
+
+private:
+  MxDSActionListCursor *m_cursor;
   undefined4 m_unk0xa0;
   undefined4 m_unk0xa4;
 };
diff --git a/LEGO1/mxpresenterlist.cpp b/LEGO1/mxpresenterlist.cpp
index ca3f15a8..1edb6e12 100644
--- a/LEGO1/mxpresenterlist.cpp
+++ b/LEGO1/mxpresenterlist.cpp
@@ -2,6 +2,7 @@
 #include "mxpresenter.h"
 
 DECOMP_SIZE_ASSERT(MxPresenterList, 0x18);
+DECOMP_SIZE_ASSERT(MxPresenterListCursor, 0x10);
 
 // OFFSET: LEGO1 0x1001cd00
 MxS8 MxPresenterList::Compare(MxPresenter *p_var0, MxPresenter *p_var1)