diff --git a/asm/include/overlay_01_02204004.inc b/asm/include/overlay_01_02204004.inc
index 3f15d87d8..a8ad276fa 100644
--- a/asm/include/overlay_01_02204004.inc
+++ b/asm/include/overlay_01_02204004.inc
@@ -55,3 +55,5 @@
 .public ov01_0220476C
 .public ov01_022047DC
 .public ov01_02204834
+.public ov01_022040C0
+.public ov01_022040E4
\ No newline at end of file
diff --git a/asm/overlay_01_02204004.s b/asm/overlay_01_02204004.s
index 7d8070620..d08c2aeb7 100644
--- a/asm/overlay_01_02204004.s
+++ b/asm/overlay_01_02204004.s
@@ -14,283 +14,6 @@
 
 	.text
 
-	thumb_func_start ov01_02204004
-ov01_02204004: ; 0x02204004
-	push {r3, r4, r5, r6, r7, lr}
-	add r6, r1, #0
-	mov r1, #0x1c
-	add r7, r0, #0
-	add r5, r2, #0
-	str r3, [sp]
-	bl Heap_Alloc
-	add r4, r0, #0
-	mov r0, #0
-	str r0, [r4, #0x10]
-	str r6, [r4, #0x14]
-	ldr r0, [sp]
-	str r5, [r4, #0x18]
-	str r0, [r4, #4]
-	add r0, r7, #0
-	add r1, r6, #0
-	bl Heap_Alloc
-	mov r2, #0
-	str r0, [r4]
-	cmp r6, #0
-	ble _0220403E
-	mov r1, #0xff
-_02204034:
-	ldr r0, [r4]
-	strb r1, [r0, r2]
-	add r2, r2, #1
-	cmp r2, r6
-	blt _02204034
-_0220403E:
-	mov r0, #0x5c
-	add r6, r5, #0
-	mul r6, r0
-	add r0, r7, #0
-	add r1, r6, #0
-	bl Heap_Alloc
-	str r0, [r4, #8]
-	ldr r1, [r4, #8]
-	mov r0, #0
-	add r2, r6, #0
-	bl MIi_CpuClearFast
-	add r0, r7, #0
-	lsl r1, r5, #2
-	bl Heap_Alloc
-	mov r6, #0
-	str r0, [r4, #0xc]
-	cmp r5, #0
-	ble _0220407E
-	add r2, r6, #0
-	add r3, r6, #0
-_0220406C:
-	ldr r0, [r4, #8]
-	add r6, r6, #1
-	add r1, r0, r2
-	ldr r0, [r4, #0xc]
-	add r2, #0x5c
-	str r1, [r0, r3]
-	add r3, r3, #4
-	cmp r6, r5
-	blt _0220406C
-_0220407E:
-	add r0, r4, #0
-	pop {r3, r4, r5, r6, r7, pc}
-	.balign 4, 0
-	thumb_func_end ov01_02204004
-
-	thumb_func_start ov01_02204084
-ov01_02204084: ; 0x02204084
-	push {r4, lr}
-	add r4, r0, #0
-	ldr r0, [r4]
-	bl Heap_Free
-	ldr r0, [r4, #8]
-	bl Heap_Free
-	ldr r0, [r4, #0xc]
-	bl Heap_Free
-	add r0, r4, #0
-	bl Heap_Free
-	pop {r4, pc}
-	.balign 4, 0
-	thumb_func_end ov01_02204084
-
-	thumb_func_start ov01_022040A4
-ov01_022040A4: ; 0x022040A4
-	push {r3, lr}
-	add r2, r1, #0
-	ldr r3, [r0, #0x10]
-	ldr r1, [r0]
-	strb r3, [r1, r2]
-	ldr r3, [r0, #4]
-	lsl r1, r2, #2
-	ldr r1, [r3, r1]
-	str r1, [sp]
-	add r1, sp, #0
-	bl ov01_02204168
-	pop {r3, pc}
-	.balign 4, 0
-	thumb_func_end ov01_022040A4
-
-	thumb_func_start ov01_022040C0
-ov01_022040C0: ; 0x022040C0
-	ldr r2, [r0, #0x10]
-	sub r3, r2, #1
-	str r3, [r0, #0x10]
-	ldr r2, [r0, #0xc]
-	lsl r0, r3, #2
-	str r1, [r2, r0]
-	bx lr
-	.balign 4, 0
-	thumb_func_end ov01_022040C0
-
-	thumb_func_start Field3dObjectList_GetRenderObjectByID
-Field3dObjectList_GetRenderObjectByID: ; 0x022040D0
-	ldr r2, [r0]
-	ldrb r2, [r2, r1]
-	cmp r2, #0xff
-	beq _022040E0
-	ldr r1, [r0, #0xc]
-	lsl r0, r2, #2
-	ldr r0, [r1, r0]
-	bx lr
-_022040E0:
-	mov r0, #0
-	bx lr
-	thumb_func_end Field3dObjectList_GetRenderObjectByID
-
-	thumb_func_start ov01_022040E4
-ov01_022040E4: ; 0x022040E4
-	push {r3, lr}
-	add r2, r1, #0
-	ldr r3, [r0, #4]
-	lsl r1, r2, #2
-	ldr r1, [r3, r1]
-	str r1, [sp]
-	add r1, sp, #0
-	bl ov01_02204168
-	pop {r3, pc}
-	thumb_func_end ov01_022040E4
-
-	thumb_func_start ov01_022040F8
-ov01_022040F8: ; 0x022040F8
-	push {r3, r4, r5, lr}
-	add r5, r0, #0
-	add r4, r1, #0
-	bl ov01_02204144
-	cmp r0, #0
-	beq _02204110
-	add r0, r5, #0
-	add r1, r4, #0
-	bl Field3dObjectList_GetRenderObjectByID
-	pop {r3, r4, r5, pc}
-_02204110:
-	add r0, r5, #0
-	add r1, r4, #0
-	bl ov01_022040E4
-	pop {r3, r4, r5, pc}
-	.balign 4, 0
-	thumb_func_end ov01_022040F8
-
-	thumb_func_start ov01_0220411C
-ov01_0220411C: ; 0x0220411C
-	push {r3, r4, r5, lr}
-	add r5, r0, #0
-	add r4, r1, #0
-	bne _02204128
-	mov r0, #0
-	pop {r3, r4, r5, pc}
-_02204128:
-	ldr r1, [r4, #0x58]
-	bl ov01_02204144
-	cmp r0, #0
-	bne _0220413E
-	add r0, r5, #0
-	add r1, r4, #0
-	bl ov01_022040C0
-	mov r0, #1
-	pop {r3, r4, r5, pc}
-_0220413E:
-	mov r0, #0
-	pop {r3, r4, r5, pc}
-	.balign 4, 0
-	thumb_func_end ov01_0220411C
-
-	thumb_func_start ov01_02204144
-ov01_02204144: ; 0x02204144
-	ldr r0, [r0]
-	ldrb r0, [r0, r1]
-	cmp r0, #0xff
-	beq _02204150
-	mov r0, #1
-	bx lr
-_02204150:
-	mov r0, #0
-	bx lr
-	thumb_func_end ov01_02204144
-
-	thumb_func_start ov01_02204154
-ov01_02204154: ; 0x02204154
-	ldr r2, [r0, #4]
-	lsl r0, r1, #2
-	ldr r0, [r2, r0]
-	cmp r0, #0
-	beq _02204162
-	mov r0, #1
-	bx lr
-_02204162:
-	mov r0, #0
-	bx lr
-	.balign 4, 0
-	thumb_func_end ov01_02204154
-
-	thumb_func_start ov01_02204168
-ov01_02204168: ; 0x02204168
-	push {r3, r4, r5, lr}
-	add r5, r0, #0
-	ldr r0, [r1]
-	add r4, r2, #0
-	bl NNS_G3dGetMdlSet
-	cmp r0, #0
-	beq _02204198
-	add r2, r0, #0
-	add r2, #8
-	beq _0220418C
-	ldrb r1, [r0, #9]
-	cmp r1, #0
-	bls _0220418C
-	ldrh r1, [r0, #0xe]
-	add r1, r2, r1
-	add r1, r1, #4
-	b _0220418E
-_0220418C:
-	mov r1, #0
-_0220418E:
-	cmp r1, #0
-	beq _02204198
-	ldr r1, [r1]
-	add r2, r0, r1
-	b _0220419A
-_02204198:
-	mov r2, #0
-_0220419A:
-	ldr r0, [r5, #0x10]
-	ldr r1, [r5, #0xc]
-	lsl r0, r0, #2
-	ldr r0, [r1, r0]
-	str r2, [r0, #0x54]
-	ldr r0, [r5, #0x10]
-	ldr r1, [r5, #0xc]
-	lsl r0, r0, #2
-	ldr r0, [r1, r0]
-	ldr r1, [r0, #0x54]
-	bl NNS_G3dRenderObjInit
-	ldr r1, [r5, #0x10]
-	ldr r2, [r5, #0xc]
-	lsl r0, r1, #2
-	ldr r0, [r2, r0]
-	add r1, r1, #1
-	str r1, [r5, #0x10]
-	str r4, [r0, #0x58]
-	pop {r3, r4, r5, pc}
-	.balign 4, 0
-	thumb_func_end ov01_02204168
-
-	thumb_func_start ov01_022041C4
-ov01_022041C4: ; 0x022041C4
-	push {r3, lr}
-	mov r1, #0x10
-	bl Heap_Alloc
-	mov r1, #0
-	str r1, [r0, #0xc]
-	str r1, [r0]
-	str r1, [r0, #4]
-	str r1, [r0, #8]
-	pop {r3, pc}
-	thumb_func_end ov01_022041C4
-
 	thumb_func_start ov01_022041D8
 ov01_022041D8: ; 0x022041D8
 	push {r3, r4, r5, r6, r7, lr}
diff --git a/include/field/overlay_01_021E8744.h b/include/field/overlay_01_021E8744.h
index 480babf50..a150e9e1b 100644
--- a/include/field/overlay_01_021E8744.h
+++ b/include/field/overlay_01_021E8744.h
@@ -2,15 +2,10 @@
 #define POKEHEARTGOLD_FIELD_OVERLAY_01_021E8744_H
 
 #include <nnsys.h>
+#include "field/overlay_01_02204004.h"
 
 typedef struct UnkStruct_ov01_021E8B04 UnkStruct_ov01_021E8B04;
 
-typedef struct UnkStruct_FieldSysC0_SubC {
-    NNSG3dRenderObj renderObj;
-    NNSG3dResMdl *model;
-    NNSG3dResFileHeader *resFileHeader;
-} UnkStruct_FieldSysC0_SubC;
-
 void ov01_021E8970(int modelNum, int animNum, int a2, UnkStruct_FieldSysC0_SubC *renderObj, void *fsysUnk54);
 UnkStruct_ov01_021E8B04 *ov01_021E8B04(int modelNum, int animNum, void *fsysUnk54);
 void ov01_021E8B84(UnkStruct_ov01_021E8B04 *anim, int a1);
diff --git a/include/field/overlay_01_02204004.h b/include/field/overlay_01_02204004.h
index ad8e2f1e0..811e99e6f 100644
--- a/include/field/overlay_01_02204004.h
+++ b/include/field/overlay_01_02204004.h
@@ -3,13 +3,24 @@
 
 #include <nnsys.h>
 
-#include "field/overlay_01_021E8744.h"
-
 #include "heap.h"
 
+typedef struct FieldSystemUnkSubC8 {
+    u32 unk0;
+    u32 unk4;
+    u32 unk8;
+    u32 unkC;
+} FieldSystemUnkSubC8;
+
+typedef struct UnkStruct_FieldSysC0_SubC {
+    NNSG3dRenderObj renderObj;
+    NNSG3dResMdl *model;
+    int index;
+} UnkStruct_FieldSysC0_SubC;
+
 typedef struct UnkStruct_FieldSysC0 {
     u8 *modelNumToLoadedSlot;
-    NNSG3dResFileHeader *resFileHeader;
+    NNSG3dResFileHeader **resFileHeaders;
     UnkStruct_FieldSysC0_SubC *objectHeap;
     UnkStruct_FieldSysC0_SubC **objects;
     int numObjects;
@@ -17,7 +28,22 @@ typedef struct UnkStruct_FieldSysC0 {
     int objectMax;
 } UnkStruct_FieldSysC0;
 
-UnkStruct_FieldSysC0 ov01_02204004(enum HeapID heapID, int indexMax, int objectMax, NNSG3dResFileHeader *a3);
-UnkStruct_FieldSysC0_SubC *Field3dObjectList_GetRenderObjectByID(UnkStruct_FieldSysC0 *a0, int a1);
+UnkStruct_FieldSysC0 *ov01_02204004(enum HeapID heapID, int indexMax, int objectMax, NNSG3dResFileHeader **fileResHeader); // FieldSysC0_New
+void ov01_02204084(UnkStruct_FieldSysC0 *unkC0); // FieldSysC0_Free
+UnkStruct_FieldSysC0_SubC *ov01_022040A4(UnkStruct_FieldSysC0 *unkC0, int index);
+UnkStruct_FieldSysC0_SubC *Field3dObjectList_GetRenderObjectByID(UnkStruct_FieldSysC0 *unkC0, int index);
+UnkStruct_FieldSysC0_SubC *ov01_022040F8(UnkStruct_FieldSysC0 *unkC0, int index);
+BOOL ov01_0220411C(UnkStruct_FieldSysC0 *unkC0, UnkStruct_FieldSysC0_SubC *object);
+BOOL ov01_02204154(UnkStruct_FieldSysC0 *unkC0, int index);
+FieldSystemUnkSubC8 *ov01_022041C4(enum HeapID heapID);
+void ov01_02204278(FieldSystemUnkSubC8 *unkSubC8);
+void ov01_02204350(FieldSystemUnkSubC8 *unkSubC8);
+void ov01_022043D8(FieldSystemUnkSubC8 *unkSubC8);
+void ov01_02204424(FieldSystemUnkSubC8 *unkSubC8);
+void *ov01_0220460C(FieldSystemUnkSubC8 *unkSubC8);
+void ov01_02204634(void *unkCC);
+void *ov01_02204744(enum HeapID heapID);
+void ov01_02204764(void *unk104);
+void ov01_022047DC(void *unk104);
 
 #endif // POKEHEARTGOLD_FIELD_OVERLAY_01_02204004_H
diff --git a/include/field_system.h b/include/field_system.h
index cb7946998..61e78c2a7 100644
--- a/include/field_system.h
+++ b/include/field_system.h
@@ -3,6 +3,7 @@
 
 #include "field/draw_map_name.h"
 #include "field/overlay_01_021E66E4.h"
+#include "field/overlay_01_02204004.h"
 
 #include "bag_cursor.h"
 #include "battle_regulation.h"
@@ -16,7 +17,6 @@
 #include "map_matrix.h"
 #include "menu_input_state.h"
 #include "overlay_01_021EB1E8.h"
-#include "overlay_01_02204004.h"
 #include "overlay_manager.h"
 #include "photo_types_def.h"
 #include "save_pokegear.h"
@@ -157,7 +157,7 @@ struct FieldSystem {
     u8 unkBC[4];
     void *unkC0;
     int unkC4;
-    FieldSystemUnkC8 *unk_C8;
+    FieldSystemUnkSubC8 *unk_C8;
     u8 filler_CC[0x4];
     u16 lastTouchMenuInput;
     u8 unkD2_0 : 6;
diff --git a/include/overlay_01_02204004.h b/include/overlay_01_02204004.h
deleted file mode 100644
index cf8de28d5..000000000
--- a/include/overlay_01_02204004.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#ifndef POKEHEARTGOLD_OVERLAY_01_02204004_H
-#define POKEHEARTGOLD_OVERLAY_01_02204004_H
-
-typedef struct FieldSystemUnkC8 FieldSystemUnkC8;
-
-void ov01_022043D8(FieldSystemUnkC8 *a0);
-void ov01_02204424(FieldSystemUnkC8 *a0);
-
-#endif // POKEHEARTGOLD_OVERLAY_01_02204004_H
diff --git a/main.lsf b/main.lsf
index 78846df19..6a52155a4 100644
--- a/main.lsf
+++ b/main.lsf
@@ -557,6 +557,7 @@ Overlay field
     Object asm/overlay_01_022031C0.o
     Object asm/overlay_01_02203A18.o
     Object asm/overlay_01_02203E40.o
+    Object src/field/overlay_01_02204004_thumb.o
     Object asm/overlay_01_02204004.o
     Object src/field/overlay_01_apricorn_tree_anim.o
     Object src/field/overlay_01_rock_smash_item.o
diff --git a/src/field/legend_cutscene_camera.c b/src/field/legend_cutscene_camera.c
index 2fc1243bb..a0de78ff9 100644
--- a/src/field/legend_cutscene_camera.c
+++ b/src/field/legend_cutscene_camera.c
@@ -4,6 +4,7 @@
 
 #include "demo/legend.naix"
 #include "field/overlay_01_021E66E4.h"
+#include "field/overlay_01_021E8744.h"
 #include "field/overlay_01_021FB878.h"
 #include "field/overlay_01_02204004.h"
 #include "fielddata/script/scr_seq/event_D17R0110.h"
diff --git a/src/field/overlay_01_02204004_thumb.c b/src/field/overlay_01_02204004_thumb.c
new file mode 100644
index 000000000..7172b48eb
--- /dev/null
+++ b/src/field/overlay_01_02204004_thumb.c
@@ -0,0 +1,103 @@
+#include "field/overlay_01_02204004.h"
+
+#include "global.h"
+
+static BOOL ov01_02204144(UnkStruct_FieldSysC0 *unkC0, int index);
+static UnkStruct_FieldSysC0_SubC *ov01_02204168(UnkStruct_FieldSysC0 *unkC0, NNSG3dResFileHeader **resFileHeader, int index);
+
+UnkStruct_FieldSysC0 *ov01_02204004(enum HeapID heapID, int indexMax, int objectMax, NNSG3dResFileHeader **resFileHeaders) { // FieldSysC0_New
+    UnkStruct_FieldSysC0 *unkC0 = Heap_Alloc(heapID, sizeof(UnkStruct_FieldSysC0));
+    unkC0->numObjects = 0;
+    unkC0->indexMax = indexMax;
+    unkC0->objectMax = objectMax;
+    unkC0->resFileHeaders = resFileHeaders;
+    unkC0->modelNumToLoadedSlot = Heap_Alloc(heapID, indexMax);
+    int i;
+    for (i = 0; i < indexMax; i++) {
+        unkC0->modelNumToLoadedSlot[i] = 0xFF;
+    }
+    int size = objectMax * 0x5C;
+    unkC0->objectHeap = Heap_Alloc(heapID, size);
+    MIi_CpuClearFast(0, (u32*)unkC0->objectHeap, size);
+    unkC0->objects = Heap_Alloc(heapID, objectMax * 4);
+    for (i = 0; i < objectMax; i++) {
+        unkC0->objects[i] = &unkC0->objectHeap[i];
+    }
+    return unkC0;
+}
+
+void ov01_02204084(UnkStruct_FieldSysC0 *unkC0) { // FieldSysC0_Free
+    Heap_Free(unkC0->modelNumToLoadedSlot);
+    Heap_Free(unkC0->objectHeap);
+    Heap_Free(unkC0->objects);
+    Heap_Free(unkC0);
+}
+
+UnkStruct_FieldSysC0_SubC *ov01_022040A4(UnkStruct_FieldSysC0 *unkC0, int index) {
+    unkC0->modelNumToLoadedSlot[index] = unkC0->numObjects;
+    NNSG3dResFileHeader *resFileHeader = unkC0->resFileHeaders[index];
+    return ov01_02204168(unkC0, &resFileHeader, index);
+}
+
+static void ov01_022040C0(UnkStruct_FieldSysC0 *unkC0, UnkStruct_FieldSysC0_SubC *object) {
+    unkC0->numObjects--;
+    unkC0->objects[unkC0->numObjects] = object;
+}
+
+UnkStruct_FieldSysC0_SubC *Field3dObjectList_GetRenderObjectByID(UnkStruct_FieldSysC0 *unkC0, int id) {
+    u8 index = unkC0->modelNumToLoadedSlot[id];
+    if (index != 0xFF) {
+        return unkC0->objects[index];
+    }
+    return NULL;
+}
+
+static UnkStruct_FieldSysC0_SubC *ov01_022040E4(UnkStruct_FieldSysC0 *unkC0, int index) {
+    NNSG3dResFileHeader *resFileHeader = unkC0->resFileHeaders[index];
+    return ov01_02204168(unkC0, &resFileHeader, index);
+}
+
+UnkStruct_FieldSysC0_SubC *ov01_022040F8(UnkStruct_FieldSysC0 *unkC0, int index) {
+    if (ov01_02204144(unkC0, index)) {
+        return Field3dObjectList_GetRenderObjectByID(unkC0, index);
+    }
+    return ov01_022040E4(unkC0, index);
+}
+
+BOOL ov01_0220411C(UnkStruct_FieldSysC0 *unkC0, UnkStruct_FieldSysC0_SubC *object) {
+    if (object == NULL) {
+        return FALSE;
+    }
+    
+    if (ov01_02204144(unkC0, object->index) == FALSE) {
+        ov01_022040C0(unkC0, object);
+        return TRUE;
+    }
+    return FALSE;
+}
+
+static BOOL ov01_02204144(UnkStruct_FieldSysC0 *unkC0, int index) {
+    return unkC0->modelNumToLoadedSlot[index] != 0xFF;
+}
+
+BOOL ov01_02204154(UnkStruct_FieldSysC0 *unkC0, int index) {
+    return unkC0->resFileHeaders[index] != NULL;
+}
+
+static UnkStruct_FieldSysC0_SubC *ov01_02204168(UnkStruct_FieldSysC0 *unkC0, NNSG3dResFileHeader **resFileHeader, int index) {
+    unkC0->objects[unkC0->numObjects]->model = NNS_G3dGetMdlByIdx(NNS_G3dGetMdlSet(*resFileHeader), 0);
+    
+    NNS_G3dRenderObjInit(&unkC0->objects[unkC0->numObjects]->renderObj, unkC0->objects[unkC0->numObjects]->model);
+    UnkStruct_FieldSysC0_SubC *object = unkC0->objects[unkC0->numObjects];
+    unkC0->numObjects++;
+    object->index = index;
+    return object;
+}
+
+FieldSystemUnkSubC8 *ov01_022041C4(enum HeapID heapID) { // FieldSystemUnkSubC8_New
+    FieldSystemUnkSubC8 *unkC8 = Heap_Alloc(heapID, sizeof(FieldSystemUnkSubC8));
+    unkC8->unkC = 0;
+    unkC8->unk0 = 0;
+    unkC8->unk4 = 0;
+    unkC8->unk8 = 0;
+}