diff --git a/src/fileio.cpp b/src/fileio.cpp
index f3a8b6d..5bf5870 100644
--- a/src/fileio.cpp
+++ b/src/fileio.cpp
@@ -77,20 +77,15 @@ std::unique_ptr<FILEIO> FILEIO::open(const char *file_name, int mode)
 	return fp ? std::unique_ptr<FILEIO>(new FILEIO(fp, mode)) : nullptr;
 }
 
-void FILEIO::ag00_gets(char *dest, int length)
+std::string FILEIO::gets()
 {
-	int p = 0;
-	
-	for(;;) {
+	std::string s;
+	for (;;) {
 		int c = getc();
-		if(c == 0x0d || c == EOF) {
+		if (c == '\r' || c == EOF)
 			break;
-		}
-		if(c != 0x0a) {
-			if(p < length + 1) {
-				dest[p++] = c;
-			}
-		}
+		if(c != '\n')
+			s.push_back(c);
 	}
-	dest[p] = '\0';
+	return s;
 }
diff --git a/src/fileio.h b/src/fileio.h
index cb65368..6b4e90f 100644
--- a/src/fileio.h
+++ b/src/fileio.h
@@ -49,7 +49,7 @@ public:
 		putc(w & 0xff);
 		putc((w >> 8) & 0xff);
 	}
-	void ag00_gets(char* dest, int length);
+	std::string gets();
 };
 
 #endif
diff --git a/src/sys/nact.cpp b/src/sys/nact.cpp
index e08fe78..133560e 100644
--- a/src/sys/nact.cpp
+++ b/src/sys/nact.cpp
@@ -34,19 +34,14 @@ NACT::NACT(const Config& config, const GameId& game_id)
 	auto fio = FILEIO::open("AG00.DAT", FILEIO_READ_BINARY);
 	if (fio) {
 		int d0, d1, d2, d3;
-		char string[MAX_CAPTION];
-		fio->ag00_gets(string, MAX_CAPTION);
-		if (sscanf_s(string, "%d,%d,%d,%d", &d0, &d1, &d2, &d3) != 4)
+		std::string line = fio->gets();
+		if (sscanf_s(line.c_str(), "%d,%d,%d,%d", &d0, &d1, &d2, &d3) != 4)
 			sys_error("AG00.DAT: parse error");
-		for(int i = 0; i < d1; i++) {
-			// 動詞の読み込み
-			fio->ag00_gets(string, MAX_CAPTION);
-			memcpy(caption_verb[i], string, sizeof(string));
+		for (int i = 0; i < d1; i++) {
+			caption_verb[i] = fio->gets();
 		}
-		for(int i = 0; i < d2; i++) {
-			// 目的語の読み込み
-			fio->ag00_gets(string, MAX_CAPTION);
-			memcpy(caption_obj[i], string, sizeof(string));
+		for (int i = 0; i < d2; i++) {
+			caption_obj[i] = fio->gets();
 		}
 		fio.reset();
 	}
@@ -312,11 +307,11 @@ void NACT::cmd_set_menu()
 
 		output_console("$");
 	} else {
-		if(!menu_index) {
+		if (menu_items.empty()) {
 			ags->clear_menu_window();
 			ags->menu_dest_y = 0;
 		}
-		menu_addr[menu_index++] = sco.getw();
+		menu_items.emplace_back(sco.getw());
 		ags->menu_dest_x = 2;
 		ags->menu_dest_y += 2;
 		ags->draw_menu = true;
@@ -324,7 +319,7 @@ void NACT::cmd_set_menu()
 		if (game_id.is_gakuen())
 			menu_window = 2;
 
-		output_console("\n$%x,", menu_addr[menu_index - 1]);
+		output_console("\n$%x,", menu_items.back().addr);
 	}
 }
 
@@ -332,7 +327,7 @@ void NACT::cmd_open_menu()
 {
 	output_console("\n]");
 
-	if (!menu_index) {
+	if (menu_items.empty()) {
 		sco.jump_to(sco.default_addr());
 		return;
 	}
@@ -343,14 +338,14 @@ void NACT::cmd_open_menu()
 		}
 	}
 
-	int selection = menu_select(menu_index);
+	int selection = menu_select(static_cast<int>(menu_items.size()));
 	if (terminate)
 		return;
 
 	if (selection != -1) {
-		sco.jump_to(menu_addr[selection]);
+		sco.jump_to(menu_items[selection].addr);
 	}
-	menu_index = 0;
+	menu_items.clear();
 }
 
 void NACT::cmd_set_verbobj()
@@ -359,12 +354,10 @@ void NACT::cmd_set_verbobj()
 	int obj = sco.getd();
 	int addr = sco.getw();
 
-	menu_addr[menu_index] = addr;
-	menu_verb[menu_index] = verb;
-	menu_obj[menu_index++] = obj;
+	menu_items.emplace_back(addr, verb, obj);
 	verb_obj = true;
 
-	output_console("\n[%x,%s,%s:", addr, caption_verb[verb], caption_obj[obj]);
+	output_console("\n[%x,%s,%s:", addr, caption_verb[verb].c_str(), caption_obj[obj].c_str());
 }
 
 void NACT::cmd_set_verbobj2()
@@ -374,14 +367,12 @@ void NACT::cmd_set_verbobj2()
 	int obj = sco.getd();
 	int addr = sco.getw();
 
-	if(condition) {
-		menu_addr[menu_index] = addr;
-		menu_verb[menu_index] = verb;
-		menu_obj[menu_index++] = obj;
+	if (condition) {
+		menu_items.emplace_back(addr, verb, obj);
 	}
 	verb_obj = true;
 
-	output_console("\n:%d,%x,%s,%s:", condition, addr, caption_verb[verb], caption_obj[obj]);
+	output_console("\n:%d,%x,%s,%s:", condition, addr, caption_verb[verb].c_str(), caption_obj[obj].c_str());
 }
 
 void NACT::cmd_a()
diff --git a/src/sys/nact.h b/src/sys/nact.h
index 899a78d..73bcfe1 100644
--- a/src/sys/nact.h
+++ b/src/sys/nact.h
@@ -77,10 +77,8 @@
 #define M_X var[57]
 #define M_Y var[58]
 
-#define MAX_MENU 64
 #define MAX_VERB 128
 #define MAX_OBJ 256
-#define MAX_CAPTION 32
 #define MAX_PCM 256
 
 class AGS;
@@ -134,7 +132,6 @@ protected:
 	void cmd_set_verbobj();
 	void cmd_set_verbobj2();
 	virtual void cmd_open_verb() = 0;
-	virtual void cmd_open_obj(int verb) = 0;
 
 	void cmd_a();
 	virtual void cmd_b() = 0;
@@ -179,13 +176,16 @@ protected:
 	bool show_push = true;		// Push表示
 	bool clear_text = true;	// メニュー後のメッセージウィンドウ消去
 
-	int menu_index = 0;			// メニュー登録のインデックス
-	int menu_addr[64];		// ジャンプ先のアドレス
-	int menu_verb[64];		// 登録された動詞
-	int menu_obj[64];		// 登録された目的語
+	struct MenuItem {
+		uint16_t addr;
+		uint8_t verb;
+		uint8_t obj;
+		explicit MenuItem(uint16_t addr, uint8_t verb = 0, uint8_t obj = 0) : addr(addr), verb(verb), obj(obj) {}
+	};
+	std::vector<MenuItem> menu_items;
 
-	char caption_verb[MAX_VERB][MAX_CAPTION];
-	char caption_obj[MAX_OBJ][MAX_CAPTION];
+	std::string caption_verb[MAX_VERB];
+	std::string caption_obj[MAX_OBJ];
 
 	bool verb_obj = false;	// 動詞-形容詞型メニューの定義中
 	bool set_palette = false;
@@ -259,7 +259,6 @@ public:
 protected:
 	void cmd_branch() override;
 	void cmd_open_verb() override;
-	void cmd_open_obj(int verb) override;
 	void cmd_b() override;
 	void cmd_d() override;
 	void cmd_e() override;
@@ -284,6 +283,8 @@ protected:
 	uint16 cali() override;
 
 private:
+	void cmd_open_obj(int verb);
+
 	// Intruder Zコマンド
 	int paint_x;
 	int paint_y;
@@ -299,37 +300,6 @@ public:
 protected:
 	void cmd_branch() override;
 	void cmd_open_verb() override;
-	void cmd_open_obj(int verb) override;
-	void cmd_b() override;
-	void cmd_d() override;
-	void cmd_e() override;
-	void cmd_g() override;
-	void cmd_h() override;
-	void cmd_i() override;
-	void cmd_j() override;
-	void cmd_k() override;
-	void cmd_l() override;
-	void cmd_m() override;
-	void cmd_n() override;
-	void cmd_o() override;
-	void cmd_p() override;
-	void cmd_q() override;
-	void cmd_t() override;
-	void cmd_u() override;
-	void cmd_v() override;
-	void cmd_w() override;
-	void cmd_y() override;
-	void cmd_z() override;
-	uint16 cali() override;
-};
-
-class NACT_Sys3 final : public NACT {
-public:
-	NACT_Sys3(const Config& config, const GameId& game_id) : NACT(config, game_id) {}
-protected:
-	void cmd_branch() override;
-	void cmd_open_verb() override;
-	void cmd_open_obj(int verb) override;
 	void cmd_b() override;
 	void cmd_d() override;
 	void cmd_e() override;
@@ -353,6 +323,39 @@ protected:
 	uint16 cali() override;
 
 private:
+	void cmd_open_obj(int verb);
+};
+
+class NACT_Sys3 final : public NACT {
+public:
+	NACT_Sys3(const Config& config, const GameId& game_id) : NACT(config, game_id) {}
+protected:
+	void cmd_branch() override;
+	void cmd_open_verb() override;
+	void cmd_b() override;
+	void cmd_d() override;
+	void cmd_e() override;
+	void cmd_g() override;
+	void cmd_h() override;
+	void cmd_i() override;
+	void cmd_j() override;
+	void cmd_k() override;
+	void cmd_l() override;
+	void cmd_m() override;
+	void cmd_n() override;
+	void cmd_o() override;
+	void cmd_p() override;
+	void cmd_q() override;
+	void cmd_t() override;
+	void cmd_u() override;
+	void cmd_v() override;
+	void cmd_w() override;
+	void cmd_y() override;
+	void cmd_z() override;
+	uint16 cali() override;
+
+private:
+	void cmd_open_obj(int verb);
 	uint16 cali2();
 
 	struct K3HackInfo;
diff --git a/src/sys/nact_sys1.cpp b/src/sys/nact_sys1.cpp
index 385fab0..ffb137b 100644
--- a/src/sys/nact_sys1.cpp
+++ b/src/sys/nact_sys1.cpp
@@ -12,6 +12,7 @@
 */
 
 #include "nact.h"
+#include <algorithm>
 #include "ags.h"
 #include "mako.h"
 #include "msgskip.h"
@@ -222,21 +223,17 @@ void NACT_Sys1::cmd_open_verb()
 	verb_obj = false;
 
 	// 表示する動詞のチェック
-	int chk[MAX_VERB], page = 0, cnt = 0;
-	
+	bool chk[MAX_VERB] = {};
+	int page = 0;
+
 	if (game_id.is_gakuen())
 		menu_window = 1;
 	int menu_max = ags->calculate_menu_max(menu_window);
 
-	memset(chk, 0, sizeof(chk));
-	for(int i = 0; i < menu_index; i++) {
-		chk[menu_verb[i]] = 1;
-	}
-	for(int i = 0; i < MAX_VERB; i++) {
-		if(chk[i]) {
-			cnt++;
-		}
+	for (const MenuItem& item : menu_items) {
+		chk[item.verb] = true;
 	}
+	int cnt = std::count(chk, chk + MAX_VERB, true);
 
 top:
 	// メニュー項目の準備
@@ -252,7 +249,7 @@ top:
 			if(chk[i]) {
 				ags->menu_dest_x = 2;
 				ags->menu_dest_y += 2;
-				ags->draw_text(caption_verb[i]);
+				ags->draw_text(caption_verb[i].c_str());
 				id[index++] = i;
 				ags->menu_dest_y += ags->menu_font_size + 2;
 			}
@@ -263,7 +260,7 @@ top2:
 			if(chk[i]) {
 				ags->menu_dest_x = 2;
 				ags->menu_dest_y += 2;
-				ags->draw_text(caption_verb[i]);
+				ags->draw_text(caption_verb[i].c_str());
 				id[index++] = i;
 				ags->menu_dest_y += ags->menu_font_size + 2;
 			}
@@ -297,7 +294,7 @@ top2:
 	} else {
 		cmd_open_obj(id[selection]);
 	}
-	menu_index = 0;
+	menu_items.clear();
 }
 
 void NACT_Sys1::cmd_open_obj(int verb)
@@ -308,27 +305,23 @@ void NACT_Sys1::cmd_open_obj(int verb)
 	verb_obj = false;
 
 	// 表示する目的語のチェック
-	int chk[MAX_OBJ], addr[MAX_OBJ], page = 0, cnt = 0;
-	
-	memset(chk, 0, sizeof(chk));
-	for(int i = 0; i < menu_index; i++) {
-		if(menu_verb[i] == verb) {
-			chk[menu_obj[i]] = 1;
-			addr[menu_obj[i]] = menu_addr[i];
-		}
-	}
-	for(int i = 0; i < MAX_OBJ; i++) {
-		if(chk[i]) {
-			cnt++;
+	bool chk[MAX_OBJ] = {};
+	int addr[MAX_OBJ], page = 0;
+
+	for (const MenuItem& item : menu_items) {
+		if (item.verb == verb) {
+			chk[item.obj] = true;
+			addr[item.obj] = item.addr;
 		}
 	}
+	int cnt = std::count(chk, chk + MAX_OBJ, true);
 	// 目的語がない場合
 	if(chk[0] && cnt == 1) {
 		sco.jump_to(addr[0]);
 		return;
 	}
 	// 以後、obj=0は戻るとして扱う
-	chk[0] = 0;
+	chk[0] = false;
 	addr[0] = sco.default_addr();
 
 top:
@@ -345,7 +338,7 @@ top:
 			if(chk[i]) {
 				ags->menu_dest_x = 2;
 				ags->menu_dest_y += 2;
-				ags->draw_text(caption_obj[i]);
+				ags->draw_text(caption_obj[i].c_str());
 				id[index++] = i;
 				ags->menu_dest_y += ags->menu_font_size + 2;
 			}
@@ -362,7 +355,7 @@ top2:
 			if(chk[i]) {
 				ags->menu_dest_x = 2;
 				ags->menu_dest_y += 2;
-				ags->draw_text(caption_obj[i]);
+				ags->draw_text(caption_obj[i].c_str());
 				id[index++] = i;
 				ags->menu_dest_y += ags->menu_font_size + 2;
 			}
diff --git a/src/sys/nact_sys2.cpp b/src/sys/nact_sys2.cpp
index 8d262aa..5b99251 100644
--- a/src/sys/nact_sys2.cpp
+++ b/src/sys/nact_sys2.cpp
@@ -255,11 +255,11 @@ void NACT_Sys2::cmd_open_verb()
 	verb_obj = false;
 
 	// 表示する動詞のチェック
-	int chk[MAX_VERB], page = 0;
-	
-	memset(chk, 0, sizeof(chk));
-	for(int i = 0; i < menu_index; i++) {
-		chk[menu_verb[i]] = 1;
+	bool chk[MAX_VERB] = {};
+	int page = 0;
+
+	for (const MenuItem& item : menu_items) {
+		chk[item.verb] = true;
 	}
 
 	// メニュー項目の準備
@@ -273,7 +273,7 @@ void NACT_Sys2::cmd_open_verb()
 		if(chk[i]) {
 			ags->menu_dest_x = 2;
 			ags->menu_dest_y += 2;
-			ags->draw_text(caption_verb[i]);
+			ags->draw_text(caption_verb[i].c_str());
 			id[index++] = i;
 			ags->menu_dest_y += ags->menu_font_size + 2;
 		}
@@ -289,7 +289,7 @@ void NACT_Sys2::cmd_open_verb()
 	} else {
 		cmd_open_obj(id[selection]);
 	}
-	menu_index = 0;
+	menu_items.clear();
 }
 
 void NACT_Sys2::cmd_open_obj(int verb)
@@ -298,13 +298,13 @@ void NACT_Sys2::cmd_open_obj(int verb)
 	verb_obj = false;
 
 	// 表示する目的語のチェック
-	int chk[MAX_OBJ], addr[MAX_OBJ], page = 0;
-	
-	memset(chk, 0, sizeof(chk));
-	for(int i = 0; i < menu_index; i++) {
-		if(menu_verb[i] == verb) {
-			chk[menu_obj[i]] = 1;
-			addr[menu_obj[i]] = menu_addr[i];
+	bool chk[MAX_OBJ] = {};
+	int addr[MAX_OBJ], page = 0;
+
+	for (const MenuItem& item : menu_items) {
+		if (item.verb == verb) {
+			chk[item.obj] = true;
+			addr[item.obj] = item.addr;
 		}
 	}
 	// 目的語がない場合
@@ -313,7 +313,7 @@ void NACT_Sys2::cmd_open_obj(int verb)
 		return;
 	}
 	// 以後、obj=0は戻るとして扱う
-	chk[0] = 0;
+	chk[0] = false;
 	addr[0] = sco.default_addr();
 
 	// メニュー項目の準備
@@ -327,7 +327,7 @@ void NACT_Sys2::cmd_open_obj(int verb)
 		if(chk[i]) {
 			ags->menu_dest_x = 2;
 			ags->menu_dest_y += 2;
-			ags->draw_text(caption_obj[i]);
+			ags->draw_text(caption_obj[i].c_str());
 			id[index++] = i;
 			ags->menu_dest_y += ags->menu_font_size + 2;
 		}
diff --git a/src/sys/nact_sys3.cpp b/src/sys/nact_sys3.cpp
index bde4eb1..abf75e4 100644
--- a/src/sys/nact_sys3.cpp
+++ b/src/sys/nact_sys3.cpp
@@ -35,11 +35,11 @@ void NACT_Sys3::cmd_open_verb()
 	verb_obj = false;
 
 	// 表示する動詞のチェック
-	int chk[MAX_VERB], page = 0;
-	
-	memset(chk, 0, sizeof(chk));
-	for(int i = 0; i < menu_index; i++) {
-		chk[menu_verb[i]] = 1;
+	bool chk[MAX_VERB] = {};
+	int page = 0;
+
+	for (const MenuItem& item : menu_items) {
+		chk[item.verb] = true;
 	}
 
 	// メニュー項目の準備
@@ -53,7 +53,7 @@ void NACT_Sys3::cmd_open_verb()
 		if(chk[i]) {
 			ags->menu_dest_x = 2;
 			ags->menu_dest_y += 2;
-			ags->draw_text(caption_verb[i]);
+			ags->draw_text(caption_verb[i].c_str());
 			id[index++] = i;
 			ags->menu_dest_y += ags->menu_font_size + 2;
 		}
@@ -69,7 +69,7 @@ void NACT_Sys3::cmd_open_verb()
 	} else {
 		cmd_open_obj(id[selection]);
 	}
-	menu_index = 0;
+	menu_items.clear();
 }
 
 void NACT_Sys3::cmd_open_obj(int verb)
@@ -78,13 +78,13 @@ void NACT_Sys3::cmd_open_obj(int verb)
 	verb_obj = false;
 
 	// 表示する目的語のチェック
-	int chk[MAX_OBJ], addr[MAX_OBJ], page = 0;
-	
-	memset(chk, 0, sizeof(chk));
-	for(int i = 0; i < menu_index; i++) {
-		if(menu_verb[i] == verb) {
-			chk[menu_obj[i]] = 1;
-			addr[menu_obj[i]] = menu_addr[i];
+	bool chk[MAX_OBJ] = {};
+	int addr[MAX_OBJ], page = 0;
+
+	for (const MenuItem& item : menu_items) {
+		if (item.verb == verb) {
+			chk[item.obj] = true;
+			addr[item.obj] = item.addr;
 		}
 	}
 	// 目的語がない場合
@@ -93,7 +93,7 @@ void NACT_Sys3::cmd_open_obj(int verb)
 		return;
 	}
 	// 以後、obj=0は戻るとして扱う
-	chk[0] = 0;
+	chk[0] = false;
 	addr[0] = sco.default_addr();
 
 	// メニュー項目の準備
@@ -107,7 +107,7 @@ void NACT_Sys3::cmd_open_obj(int verb)
 		if(chk[i]) {
 			ags->menu_dest_x = 2;
 			ags->menu_dest_y += 2;
-			ags->draw_text(caption_obj[i]);
+			ags->draw_text(caption_obj[i].c_str());
 			id[index++] = i;
 			ags->menu_dest_y += ags->menu_font_size + 2;
 		}