diff --git a/asm/include/unk_02018380.inc b/asm/include/unk_02018380.inc
deleted file mode 100644
index 5618ece3eb..0000000000
--- a/asm/include/unk_02018380.inc
+++ /dev/null
@@ -1,8 +0,0 @@
-#include <nitro/fs/overlay.h>
-#pragma once
-.public sub_02018380
-.public sub_0201838C
-.public sub_020183B0
-.public sub_020254FC
-.public sub_02025504
-.public AddIGTSeconds
diff --git a/asm/unk_02018380.s b/asm/unk_02018380.s
deleted file mode 100644
index b9af8f43f6..0000000000
--- a/asm/unk_02018380.s
+++ /dev/null
@@ -1,75 +0,0 @@
-	.include "asm/macros.inc"
-	.include "unk_02018380.inc"
-	.include "global.inc"
-
-	.bss
-
-_021D10E8:
-	.space 0x20
-
-	.text
-
-	thumb_func_start sub_02018380
-sub_02018380: ; 0x02018380
-	ldr r0, _02018388 ; =_021D10E8
-	mov r1, #0
-	str r1, [r0]
-	bx lr
-	.balign 4, 0
-_02018388: .word _021D10E8
-	thumb_func_end sub_02018380
-
-	thumb_func_start sub_0201838C
-sub_0201838C: ; 0x0201838C
-	push {r3, lr}
-	ldr r1, _020183AC ; =_021D10E8
-	mov r2, #1
-	str r2, [r1]
-	mov r2, #0
-	str r2, [r1, #0x10]
-	str r2, [r1, #0x14]
-	str r2, [r1, #8]
-	str r2, [r1, #0xc]
-	str r0, [r1, #4]
-	bl sub_020254FC
-	ldr r2, _020183AC ; =_021D10E8
-	str r0, [r2, #0x18]
-	str r1, [r2, #0x1c]
-	pop {r3, pc}
-	.balign 4, 0
-_020183AC: .word _021D10E8
-	thumb_func_end sub_0201838C
-
-	thumb_func_start sub_020183B0
-sub_020183B0: ; 0x020183B0
-	push {r3, r4, r5, lr}
-	ldr r0, _020183EC ; =_021D10E8
-	ldr r0, [r0]
-	cmp r0, #0
-	beq _020183EA
-	bl sub_020254FC
-	ldr r2, _020183EC ; =_021D10E8
-	ldr r3, [r2, #0x18]
-	ldr r2, [r2, #0x1c]
-	sub r0, r0, r3
-	sbc r1, r2
-	bl sub_02025504
-	add r5, r1, #0
-	ldr r1, _020183EC ; =_021D10E8
-	add r4, r0, #0
-	ldr r3, [r1, #8]
-	ldr r2, [r1, #0xc]
-	sub r0, r3, r4
-	sbc r2, r5
-	bhs _020183EA
-	ldr r0, [r1, #4]
-	sub r1, r4, r3
-	bl AddIGTSeconds
-	ldr r0, _020183EC ; =_021D10E8
-	str r4, [r0, #8]
-	str r5, [r0, #0xc]
-_020183EA:
-	pop {r3, r4, r5, pc}
-	.balign 4, 0
-_020183EC: .word _021D10E8
-	thumb_func_end sub_020183B0
diff --git a/include/unk_02018380.h b/include/unk_02018380.h
index 5363b6c61c..6cf0f3935a 100644
--- a/include/unk_02018380.h
+++ b/include/unk_02018380.h
@@ -3,8 +3,17 @@
 
 #include "igt.h"
 
+typedef struct UnkStruct_021D10E8 {
+    u32 unk0;
+    IGT *igt;
+    u64 unk8;
+    u32 unk10;
+    u32 unk14;
+    u64 unk18;
+} UnkStruct_021D10E8;
+
 void sub_02018380(void);
 void sub_020183B0(void);
-void sub_0201838C(IGT* igt);
+void sub_0201838C(IGT *igt);
 
 #endif //POKEHEARTGOLD_UNK_02018380_H
diff --git a/main.lsf b/main.lsf
index efa6006939..a4bfc48394 100644
--- a/main.lsf
+++ b/main.lsf
@@ -57,7 +57,7 @@ Static main
 	Object asm/unk_02016EDC.o
 	Object asm/unk_02017FAC.o
 	Object asm/unk_02018000.o
-	Object asm/unk_02018380.o
+	Object src/unk_02018380.o
 	Object asm/unk_020183F0.o
 	Object src/camera_translation.o
 	Object asm/unk_020192D0.o
diff --git a/src/unk_02018380.c b/src/unk_02018380.c
new file mode 100644
index 0000000000..8d58494c39
--- /dev/null
+++ b/src/unk_02018380.c
@@ -0,0 +1,33 @@
+#include "global.h"
+#include "unk_02018380.h"
+#include "timer_3.h"
+
+static UnkStruct_021D10E8 s_021D10E8;
+
+void sub_02018380(void) {
+    s_021D10E8.unk0 = 0;
+}
+
+void sub_0201838C(IGT *igt) {
+    s_021D10E8.unk0 = 1;
+    s_021D10E8.unk10 = 0;
+    s_021D10E8.unk14 = 0;
+    s_021D10E8.unk8 = 0;
+    s_021D10E8.igt = igt;
+    s_021D10E8.unk18 = sub_020254FC();
+}
+
+void sub_020183B0(void) {
+    if (s_021D10E8.unk0 == 0) {
+        return;
+    }
+
+    u64 val = sub_020254FC();
+    u64 val2 = sub_02025504(val - s_021D10E8.unk18);
+    if (s_021D10E8.unk8 >= val2) {
+        return;
+    }
+
+    AddIGTSeconds(s_021D10E8.igt, val2 - s_021D10E8.unk8);
+    s_021D10E8.unk8 = val2;
+}